Peculiar plants and fantastic fungi: An ethnobotanical study of the use of hallucinogenic plants and mushrooms in Slovenia

The present study examined the patterns of use among a sample of 68 users of hallucinogenic plants and mushrooms in Slovenia. In compiling the lists of all the participants, 26 different plants/mushrooms, mixtures, or products were found to have been used. The main reason for beginning to use these substances was curiosity, and most people began using them in their 20s. The most used were Psilocybe spp., being mentioned by approximately 91% of the participants; 50% of the respondents in the study had made use of no other natural hallucinogens besides these. Many of the plants or mushrooms were used only a small number of times. No matter what items had been used, the internet often played a role in first hearing about them. Dosing and the means of using the various hallucinogens were often quite varied, as were the settings where they were taken. Knowledge of the dangers of these hallucinogenic plants and mushrooms as well as their occurrence in nature were likewise vastly varied. Though public opinion often associates the use of mind-altering substances with problematic drug use and partying, the majority of the individuals interviewed seemed to present a greater desire to experience the interesting effects, to overcome personal difficulties, and for individual and spiritual growth.


Introduction
Use of hallucinogenic plants and fungi, believed to extend back thousands of years, is an important part of the human experience [1]. Whether used for healing, divination, magic, or protection, these biological wonders have served an important role in the development of cultures and have captured the imagination of many.
Though many words have been used to describe these substances, perhaps the most widely accepted is hallucinogens. The term hallucinogen first became popular in the 1950s and was originally used as the substances were said to produce hallucinations, though we now know that this is often not the case at lower doses [2,3]. The main effects of these substances are on perception, mood, and thought, and at lower doses they display minimal intellectual impairment and no disabling effects; they are also not physically addictive [4,5]. These effects a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 are often characterised as being dreamlike and are marked by sensory distortions and sometimes true hallucinations (often visual or audio), exaggeration of emotional state, distortion of time, mystical qualities, and various spiritual experiences and revelations such as ego dissolution, feeling of a near death experience, and a sense of universal connection or understanding [2,6,7]. The effect of set and setting (mental state and physical environment) in taking these substances is also known to be important [2].
After a wave of concern in regards to these substances in the 1970s, they came to be used less frequently [7]. They began to witness a revival during the 1990s, one that has been further strengthened by the spread of the internet [8,9]. As such, their present usage is of great interest from a variety of perspectives, including medicinal, social, legal, and ethnobotanical.
The present study seeks to add to the literature on the modern use of hallucinogenic plants and mushrooms, with a population set in Slovenia. Though the use of mind-altering substances is often broadly stereotyped, the individuals in this study showed a range of motivations for their use, demonstrating that further investigation is warranted from a range of disciplines.

Methods
Participants were gathered through the dissemination of advertisements both on social media and by posters placed around the capital city of Slovenia. Word of mouth between participants also accounted for many of the recruitments.
Participants were given the option to be interviewed in person or to complete an online questionnaire, for those living further away or uncomfortable sharing the information in person.
Participants were informed of the purpose of the project, how results would be disseminated, and that they could retract their answers prior to publication. They were told that they would remain anonymous, though Dr. Roman Paškulin asked to be named. These steps were undertaken to ensure informed consent, which was obtained verbally in the case of the in-person interviews; for those completing a questionnaire, the information about the project and the informed consent were included before the first questions.
Questionnaires were shared online, and structured interviews based on the questionnaire were used for in-person gathering and were recorded with participant consent. Data was collected between September 2018 and December 2019 and was then analysed qualitatively and with basic statistics.
has been stated to consistently show users of hallucinogenic plants to range from 14-56 years of age with a mean of 26, quite close both to the mean age of this sample group [28] and to the average age of first use for all the substances (27) [10].
The youngest first use was Myristica fragrans Houtt. (16) and the oldest Psychotria viridis Ruiz & Pav (50), though both were listed only once; it may thus be better to use only plants listed by two or more individuals in considering this, thus making the lowest average age of first use Datura spp. L. (18) and the oldest Echinopsis pachanoi (Britton & Rose) Friedrich & Rowley (35). Datura is known to be used by young people in Slovenia and beyond, making this unsurprising, while E. pachanoi may owe its delayed first use to its foreign home, difficulty to obtain, and high price [9,[11][12][13].
It is also interesting to note that the average age of first use for local Psilocybe (Fr.) P. Kumm. spp. was higher than that for foreign ones; though this may be a result of the smaller sample size for the former group, it could also show that foreign mushrooms served as an introduction to the world of hallucinogenic fungi, with local ones tried later when the individuals were more comfortable with them and felt sufficiently knowledgeable to find and harvest mushrooms themselves.
Participants rated the difficulty of obtaining substances from 1 (easiest) to 5 (hardest). The lowest average ratings were substances collected in nature or bought legally and cheaply; those that were difficult to get came from other countries, unsafe internet sources, shamans or dealers, and often were more expensive. However, the scale was subjective: some rated ayahuasca as 1, while others listed Psilocybe spp. as 5. Though this represents each individual's sense, the objective difficulty of obtaining ayahuasca in Slovenia is certainly not lower than that of Psilocybe spp.
It often came down to whom the participants knew, with many stating for the more exotic plants that they could be easily obtained with the right contacts. People who used many plants and mushrooms (or used them repeatedly) tended to rate the difficulty of finding such substances lower than those who had used only Psilocybe spp. and who had perhaps used them just once. Many individuals also stressed that in the capital it is much easier to find such substances than in rural areas. Many who picked the hallucinogenic plants and mushrooms also noted the importance of the season on availability.
A list of average ages of first use and difficulty to obtain ratings may be seen in Table 1.

Psilocybe spp.
Perhaps the most well-known natural hallucinogen worldwide, Psilocybe mushrooms are members of the Hymenogastraceae and the most common genus of psychoactive fungi [14]. Mushrooms of this genus have a long history of use in shamanic rituals in Mexico and are psychoactive as a result of containing psilocybin, a compound that is then broken down in our digestive system into psilocin, the true hallucinogenic alkaloid [2,[14][15][16]. Research has consistently shown the use of these mushrooms to be safe with no direct physical damage being caused, though there are low but significant rates of flashbacks and panic attacks associated with taking these fungi, which may make them unsuitable for those with heart issues [14,[16][17][18]. Research in France with users of hallucinogenic plants and mushrooms showed that all 30 individuals interviewed for a study had previously used Psilocybe spp., while in the Czech republic, over 30% of reported toxicology cases were a result of the use of these mushrooms [8,9]. In this study, Psilocybe spp. were the most listed item, appearing 62 times, and had the greatest variety of names. Some were Latin or English; most were Slovene, often including the word for mushrooms (gobe, gobice) or fungi (glive) and adjectives describing their effects (Čarobne/magical, nore/crazy, halucinogene/hallucinogenic, psihadelične/psychedelic, čudežne/ miraculous). Names for all items listed may be seen in Table 1.
Two categories emerged: foreign and local mushroom use. Friends and the internet were the most common ways to first hear of foreign mushrooms, and the main motivation for trying them was curiosity. Use frequency was usually 2-4 times per year. Many noted decline in use as they aged, though whether this is due to a decreased need for exciting experiences or no longer requiring the benefits was often unclear. Continued use was usually due to pleasant and beneficial effects while lack of access and high price were the main reasons for discontinuing. Most ate them whole and dried. The next most common method was grinding dried mushrooms into juice; many believed lemon juice enhanced the trip. Microdoses usually ranged from 0.05-0.2 g, while large doses were usually 3-4 g. Foreign mushrooms were usually used without other substances, though many combined them with marijuana and occasionally with other intoxicants. They were mainly used in the evening, though there was a preference for daytime use in summer when it was possible to go outside. Participants were roughly divided in half between using them inside or in nature. Some used them at parties. The main condition was usually to be somewhere safe, usually at home or in nature far from populated areas. Weekends were preferred. Most used Psilocybe spp. in small groups. Only a few always used them alone.
Foreign mushrooms were usually received from "friends," though one individual noted that dealers often become friends, thus making the exact distinction unclear. Some participants grow foreign mushrooms, usually from grow kits bought online. Most received the mushrooms whole and dried. 5€ per gram and 6-10€ per gram were the most frequently stated prices. Many had difficulty describing the effects; visual alterations involving patterns/shapes/ textures were most reported. Dangers were mainly mentioned in relation to predispositions to mental health issues, especially schizophrenia, followed by the danger of having a bad trip, though this effect was infrequently reported in the present study. Some believed that these exact mushrooms grew in Slovenia, clearly mistaking them for local varieties.
Five participants used local Psilocybe spp. (likely P. semilanceata [Fr.] P. Kumm. based on descriptions, though it is worth noting that nearby countries have published ecological findings that suggest a richness in the variety of hallucinogenic fungal species in the area [19]), with one never having used foreign ones. Dosing ranged from 3-25 mushrooms, or 1-5 g, significantly lower than in previously published research from Poland [18]. All but one participant picked the mushrooms themselves. They were often compared to foreign mushrooms but said to be stronger. Participants stated that they are not hard to get, but you need to know when and where they grow and how to identify them, as well as having a means of getting to them.
2 participants who used foreign Psilocybe spp. also listed Psilocybe truffles. Both got them in Amsterdam or from someone who had been there and described them like foreign Psilocybe spp.
With all Psilocybe mushrooms together, they were one of the few plants or mushrooms to be the sole element listed by some. These were the most often to occur in this sense, being the sole item listed by 34 individuals. They were co-listed with Salvia divinorum Epling & Játiva 16 times, the highest frequency of co-occurrence between any listed items. The complete analysis of co-listing for all plants and mushrooms may be seen in Table 2.
Responses are summarised in Table 3.
In the present study, Salvia divinorum was the second most used substance, listed 16 times. It was mainly first heard of on the internet. Curiosity was the main reason to try it. Most used this plant once before discontinuing due to availability or lack of desirable effects. 2 chewed the leaves, one made and smoked an extract from leaves, and all other participants smoked dried leaves. Smoking was often communal and thus the exact amount ingested unknown. Most used this plant without other substances; a couple included tobacco to their smoking mix, while alcohol, marijuana, and MDMA were also sometimes combined. The plant was almost always used with other people, mainly outside.
Salvia divinorum was most frequently obtained as whole, dried leaves, though plant cuttings were also often mentioned. Most participants received the plant free from friends. One participated in a ritual involving this plant and that cost between 100 and 250€. Buying this plant on the internet was said to be risky.
Effects were described as lasting about 5 minutes and being intense when smoked, or lasting a couple of hours and being mild when chewed. An intense high was the most reported effect along with euphoria, though directly following this were claims that there had been no effect. The most listed danger of this plant was causing harm to yourself while high.
Responses are summarised in Table 4.

Ayahuasca
Unlike the majority of items here discussed, ayahuasca is not a plant, but rather a mixture. Native to the Amazon, ayahuasca is a beverage traditionally used by shamans to help with divination and healing; there is a large ritual system built around using this mixture, which serves an important social-cohesion function [32,33]. Though the ingredients used to create ayahuasca vary, the generally mentioned main ingredients are the bark of the vine Banisteriopsis caapi (Spruce ex Griseb.) Morton and the leaves of Psychotria viridis [5,34]. P. viridis leaves are a source of N,N-dimethyltryptamine, better known as DMT; this substance works on serotonin receptors to cause its effects [35,36]. However, it is not orally active as it is decomposed in the stomach; for it to be effective when ingested orally, it must be taken with a monoamine oxidase inhibitor (MAOI) that prevents rapid breakdown [16,36]. B. caapi bark is rich in harmala alkaloids such as harmine and harmaline, which function in exactly this manner [35,36]. Combining the two creates a beverage that is orally active as a hallucinogen. As these two plants grow in a limited range of the world's tropical habitat, many have created "ayahuasca analogues" by combining other more widespread plants that contain the same alkaloids [37]. Ayahuasca became popular outside the Amazon in the 1990s, and since has seen a rise in use around the world, as well as in "ayahuasca tourism," in which individuals travel to the Amazon in order to participate in rituals [34,37]. Though ayahuasca tourism is criticised as being a radicalised form of recreational drug use, research suggests that users undergoing these voyages do so seeking spiritual growth or to help with psychological conditions [38,39]. Though legally questionable in many countries outside of Amazonia, its status as a spiritual sacrament for some recognised religious groups has led to increased acceptance [40][41][42][43][44][45][46].
Dosage varied, and one participant noted that less is needed as you become experienced in using it. Most used ayahuasca without other substances, though hapé (a psychoactive snuff), Echinopsis pachanoi, and Erythroxylum P. Browne leaves were sometimes consumed with it, as directed by shamans. Most said ayahuasca should be taken in the evening so the effect runs through the night and that there should be free days after taking it. Most used ayahuasca in the presence of others.
All received ayahuasca as a prepared beverage, buying it directly or participating in ceremonies in Slovenia and abroad. Workshops/rituals in Slovenia were mainly suggested to cost 100-250€. Buying ayahuasca independently in Slovenia was said to cost between 40-100€. Participants stated that it is easier to find the past few years in Slovenia, and that it is not difficult once you have connections. The price of rituals was listed as a barrier.

PLOS ONE
The most listed effect of ayahuasca was vomiting. One participant felt ayahuasca was completely safe, but the others listed various dangers.
Ayahuasca was one of the few substances to be listed alone, with one person who had used it never having tried other hallucinogenic substances.
Responses are summarised in Table 4.

Amanita muscaria
This Agaricaceae mushroom was traditionally used as a ritual hallucinogen in Siberia [35,47]. Its psychoactivity is caused by ibotenic acid and muscimol [48]. Muscimol is more hallucinogenic, and seasonal variation in the strength of this mushroom likely results from shifting ratios between these substances [49]. Effects are dependent on preparation, as dehydration changes ibotenic acid into muscimol, which is also more readily extracted in water; water infusions may help leave behind substances responsible for unpleasant physical effects [48]. Previous research from France and the Czech republic have shown minimal use, though it has been becoming increasingly popular in Poland over the recent years [8,9,50].
In the present study, 10 participants listed Amanita muscaria (L.) Lam. The internet was the main introduction to this mushroom as a hallucinogen. Most heard of it from family members as children and believed it to be poisonous. Curiosity was the main reason to try. Only one participant uses the mushroom regularly, the others having discontinued due to nausea. Given the importance of preparation, it is unsurprising these individuals had undesirable experience-only one individual dried the mushroom and then infused it into water, while all others directly consumed it. Most noted the taste to be disgusting. Dosing ranged from an 8 cm diameter portion of the cap up to 1.5 mushrooms. It was mainly used without other substances, with one participant even noting that it absolutely must be taken alone and cautioned that the mushrooms could be greatly varied in strength. It was almost exclusively used in nature while in the presence of others.
The most frequently listed effect was nausea. Multiple participants stated that their perception shifted in significant ways, but without actual hallucinations. Half suggested it could be dangerous in ways related to the nausea it causes. Most described the mushroom as red with white spots, stating that they grow in forests. The northern region of Slovenia was said to be a good area for finding them.
Responses are summarised in Table 5.

Echinopsis pachanoi
This member of the Cactaceae is made hallucinogenic by mescaline, a phenethylamine [14].
Research in France has shown that less than a third of hallucinogenic plant users had tried this plant, with those who had done so electing to consume it as a tea or by cooking the cactus to make a sort of dough that was swallowed [8]. 7 participants used this plant in the present study. Books and the internet were the main ways of finding out about this cactus; the main motivation for trying it was curiosity. Three used this plant only once, mainly discontinuing due to availability. Those who took it 2-3 times were seeking a better effect than the first trip, but stopped due to unpleasant effects such as nausea, the most commonly listed effect.
Mainly consumed as a beverage, dosing was described various ways. One participant took this plant during an ayahuasca ceremony, but the others used it without other substances; one individual stressed that it must be taken alone. All but one participant used the cactus in the presence of other people and use was primarily inside.
Most participants obtained E. pachanoi from a shaman, though one grows it at home after buying it in a local shop where it was being sold as a houseplant. Participants were divided on whether or not the cactus is dangerous.
Responses are summarised in Table 5.

Datura spp.
As with the other plants from the family Solanaceae in this study, Datura spp. are hallucinogenic and highly toxic as a result of the anticholinergic tropane alkaloids hyoscyamine and scopolamine, which act as muscarine receptor antagonists [36,51]. These plants have a long history of recreational use; in parts of France, the seeds were mixed with cider for farmers to consume after a day's work [52]. More recent work in France has found that almost half of hallucinogenic plant users have experimented with Datura, with many of them using it only once Place of use Outside [4], inside [2] At home [3], outside [2], inside during ceremony [1] Use with others or alone With others [5], alone [1] With others [4], alone [1] Methods of obtaining Collected in nature [7] Shaman [3], internet [2], acquaintance [1], grown at home [1] State when obtained Fresh [7] Beverage [3], fresh [2], dried and cut [ Natural knowledge Red cap with white dots [3], grows in forests [2], grows in Slovenia [2], grows around pine [1], grows around fir [1], grows in the forests in northern Slovenia [1], does not grow around beech [1], forms symbiotic relationship with trees [1] Cactus [1], from tropical climates [1], requires abundant sunlight [1], can grow several metres tall [1], cross section usually a 5-pointed star [1], from Peru [1] https://doi.org/10.1371/journal.pone.0245022.t005 due to the "dark" and negative experiences [8]. Toxicology centres in France have likewise seen many cases as a result of the abuse of these plants, a trend also seen in other countries such as Spain, Germany, Poland, and the Czech Republic [9,10,[53][54][55]. Toxicology reports in Slovenia have had similar findings, with D. stramonium L. being the highest source of drug-related plant intoxications in the country [11]. These sources point toward one-time usage among teens, often as a result of peer pressure, as being the main source of drug use for Datura spp.
In the present study, 6 individuals used Datura spp. All used D. stramonium, while one also used D. innoxia Mill., which they stated was stronger. Half used it only once, with bad experiences causing discontinuation. One participant used repeated microdoses to enhance their dreaming but discontinued after an accidental large dose. Only one participant uses the plant regularly, doing so twice a year to obtain a state of inner peace.
Many learned of Datura spp. by knowing people who had taken it and curiosity was why many tried it. Seeds were usually used, generally 2-10. Only one participant took it while alone. One individual grew the plant, while the others collected it in nature. Slovenia's coastal region was noted as a place where it grows abundantly, though I have personally observed it far more often in the central region of the country.
The most commonly listed effects were loss of touch with reality and temporal distortion. Many other negative effects were listed; one participant wandered naked through the city, waking 40 km from home. Participants agreed that the plant is dangerous, with one specifying that the recreational dose is close to the toxic dose.
Responses are summarised in Table 6.

Ipomoea spp.
Members of the Convolvulaceae family, Ipomoea L. spp. are vines from the Americas that are now widespread garden plants [14,56]. The taxonomy is complicated as both I. tricolor Cav. and I. violacea L. are considered hallucinogenic, though many authorities say they are the same species; similarly, I. purpurea (L.) Roth is sometimes stated to be hallucinogenic, though many believe it is not [14,57]. The seeds of hallucinogenic species contain ergine, otherwise known as lysergic acid amine (LSA), a substance similar to LSD [14,16,56]. Research in Poland suggests usage for these plants as hallucinogens is low, stating that the unpleasant gastrointestinal side effects may deter users [57]. Toxic coatings used on seeds sold in stores may likewise be a deterrent [16]. A study in France found less than one third of hallucinogenic plant users had employed these seeds [8].
In the present study, 5 individuals listed this plant, most having heard about it through the internet. Curiosity was the main reason to try it. Those who used it multiple times did so as they felt they had begun at too low a dose. Unpleasant side effects were the reason for discontinuing.
All participants used the seeds: 3 eating them, one infusing them into water, and one infusing ground seeds into water, which was then evaporated and infused in alcohol. Most tried 5 to 25 seeds, but one used 150. One participant took garlic with the seeds, believing this would combat the nausea. All participants used this plant at home, and almost all while alone.
2 bought the seeds from garden stores, selecting those without toxic coatings. 2 collected the seeds from gardens of people they knew. The price was suggested to be 1-2€ per package (~30 seeds), while those who collected the seeds had never heard of them being sold.
The most frequently reported effects were nausea, heightened imagination, and no effect. One individual began experiencing panic attacks regularly after using these seeds, a state that lasted for a year and even caused agoraphobia.
Responses are summarised in Table 6.

Lophophora williamsii
A small, slow-growing cactus found around the border of the USA and Mexico, this member of the Cactaceae family is known for its ritual use that may extend back almost 6000 years [14,16,56]. The hallucinogenic effects of this cactus are attributable to mescaline, though some theorise that other compounds also play a role [56,58]. Research in France found 9 of 30 participants had used either L. williamsii (Lem. ex Salm-Dyck) J. M. Coult or E. pachanoi, primarily by making them into tea, cooking them and creating a dough from them, or merely swallowing them raw [8]. 5 participants in the present study listed this plant, mainly first having heard of it through books and trying it due to curiosity. Most used this cactus only once, with availability keeping them from further experiences, though one individual stated that they ceased using it out of Table 6. Overview of Datura spp. and Ipomoea spp.
Most used the plant with other people, one during shaman-led ceremonies. Two participants grow the plant themselves after finding it at local flower shops where it was being sold as a house plant. Participants mentioned a range of mild hallucinogenic effects. Antidepressant aftereffects were also reported.
Responses are summarised in Table 7.

Tabernanthe iboga
Africa is the place of origin of few hallucinogenic plants, but the most famous is Tabernanthe iboga Baill. [59]. From the alkaloid-rich Apocynaceae family, this plant is known for its ritual use among the Bwiti [47,56]. The hallucinogenic alkaloid, ibogaine, inhibits serotonin transport in the central nervous system to cause its psychoactive effects [60]. It seems to not have found much use outside of Africa; a study in France found only one participant of 30 had used this plant, doing so after getting it as a powder and rolling this into a ball to chew [8].

Lophophora williamsii Tabernanthe iboga
How first heard of Books [3], friends [1], internet [1] Books [2], internet [1] Why first tried Curiosity [3], offered by a friend [1], experience another reality and reduce ego [1] Curiosity [2], diminish ego [1] Number of times used Once [3], 3 times [1], twice per year [1] 2 large doses when younger and now microdoses twice per year [1], once [1] Reasons for discontinuing use Availability [2], respect for plant [1] Stopped with large doses because no longer needed to learn from the plant [1], only available once [1] Reasons for continuing use Experience power of the plant [1] Microdoses to strengthen/clean/sharpen mind [1] Method of consumption Chew raw or dried buttons [2], tea [1], dried buttons ground into water [1] Powdered root bark or alcohol extraction eaten [1], cream on skin [ Yellow fruits [1], from the jungle in Africa [1] https://doi.org/10.1371/journal.pone.0245022.t007 3 individuals listed this plant in the present study. One only used a small amount of cream with it at a conference, while the other 2 made greater use. The 2 repeat users were at odds as to the difficulty to obtain this plant: one participant brought it from Africa and listed it as 5 out of 5, while one participant receives it in ceremonies and listed it as 1 out of 5, saying that it is easy to get with the right contacts.
Responses are summarised in Table 7.

Argyreia nervosa
From the family Convolvulaceae, this plant is from the Indian sub-continent, where it has traditionally been used for a range of medical conditions and is incorporated into the Ayurvedic pharmacopoeia [61]. It is now widely grown as an ornamental for its showy flowers, and the seeds are often coated with toxic substances as with Ipomoea spp. to discourage using them for their LSA content [16,61]. First becoming widespread in the 1990s, research in France found that almost one third of study participants had tried this plant, often using 5-15 seeds [8]. This same study found that the seeds of A. nervosa (Burm. F.) Bojer were often used only once or twice, with low availability often cited as a reason for discontinuing [8]. A similar study in Poland noted that 6-8 seeds are normally employed, and states that gastrointestinal side effects were often what caused discontinuation, while, opposite to the previous study, stating that low price and ease of access were often reasons for use [57]. 3 participants listed this plant in the present study, mainly hearing of it through the internet. One used the seeds just once due to accessibility and as they developed panic attacks after taking them, while one takes the seeds annually. Both ate the seeds without other substances, one taking 6-8 and the other unsure of the amount. Both took the seeds with other people; one added that the feeling of telepathy made taking them in a group best. One participant bought capsules filled with seeds in a shop, stating that they cost about 12€ for 4 capsules.
One participant likened the effect to Ipomoea spp. seeds, though more dangerous as it produces a more profound experience that was stated to affect women more than men, though the participant to claim this was a cisgender male.
Responses are summarised in Table 8.

Atropa belladonna
Native through parts of Europe, this member of the Solanaceae was the first plant to have the tropane alkaloid atropine (the racemic mixture of hyoscyamine enantiomers) isolated from it [36,51,62]. Its hallucinatory and lethal effects have been known since ancient times, and many claim that it was once used in the ointments that witches of Medieval Europe would use to give themselves the illusion of flying [56,62]. It was heavily abused during the mid-to-late 1900s as it was used in commercial products for asthma; these products were often used as recreational drugs, frequently with dangerous results [63]. Even since the discontinuation of such products, Atropa belladonna L. has found use as a hallucinogen. A study of Spanish poison control found that 7.3% of the calls related to intentional plant exposures were due to this plant, while a German study of inpatients with substance abuse problems displayed a fair number of users [10,54]. A similar study carried out in Slovenia displayed that A. belladonna was the fourth most common cause of plant poisonings in the country, with these cases being a mix of attempted suicides and recreational use [11]. Nearby in the Bilogora region of Croatia, there even existed a tradition of boys taking the berries to amuse themselves during time spent herding flocks in the mountains [64].
In the present study, Atropa belladonna was listed by 3 participants. One read about the plant on the internet, and used it a few times since they liked the effect; another learned of it through existing folk traditions and as part of this uses it about twice per year. The regular user does so by eating the berries or cooking the leaves in wine, while the participant to use the plant a few times did so by cooking dried leaves in coconut oil to make an ointment, usually applied in nature. They noted lightness of their legs and changes to their visual perception, with it being easier to see darker rather than lighter areas; these symptoms would make sense, given that the alkaloids of this plant are said to have caused a feeling of flying when used by European witches and since they dilate the pupils, which would allow more light into the eyes [16,56]. This plant was used alone, though the regular user noted that they occasionally added the leaves to Hyoscyamus niger L. ointments. Both collect the plant in nature.
Responses are summarised in Table 8.

Artemisia spp.
A member of the Asteraceae family, Artemisia L. spp. are famous for the role of A. absinthium L. in making absinthe. Though there are many debates around whether or not absinthe was hallucinogenic, many Artemisia spp. produce a range of secondary metabolites, the most known perhaps being thujone, a GABA receptor modulator [65,66]. Though not proven hallucinogenic, many believe it to be, and some have gone so far as to try it themselves to confirm this [67]. 3 participants listed Artemisia spp. in the present study. Only one used it regularly, doing so over 5 years in the form of alcoholic beverages. It was curiosity that drove 2 participants to try Artemisia spp., while the third did so to increase the intensity of their dreams. No

Argyreia nervosa Atropa belladonna
How first heard of Internet [2], Blue light [1] Internet [1], folk tradition [1] Why first tried Reach altered state of consciousness [1], curiosity and convenience [1] Interest in effects [1], desire to join folk tradition [1] Number of times used Once [1], once per year [1] A few times [1], twice per year [1] Reasons for discontinuing use Only had access once [1] Reasons for continuing use Pleasant feeling of telepathy [1] Enjoyed the effects [1], desire to feel the power of the plant [1] Method of consumption Seeds eaten [2] Berries eaten or leaves cooked in wine [1], leaves cooked in coconut oil and applied to skin [1] Dose Unsure [1], 6-8 seeds [1] Double handful of leaves in a handful of oil [1] Use with other substances Alone [2] Alone [1] Time of use Day [1], evening [1] Place of use Home [1], nature [1] Nature [2] Use with others or alone With others [2] Alone and with others [1], with others [1] Methods of obtaining From a friend [2], from a store [1] Collected in nature [2] State when obtained Seeds [2], seeds in capsules [1] Fresh [2] Cost Unsure [2], 12€ for 4 capsules [1] Free [2] Effects Telepathy [1], clarity to life problems [1], similar to Ipomoea spp. [1], vivid colour vision [1], enhanced imagination [1], feeling sounds [1], nausea [1], anxiety [1] Unable to describe [1], seeing dark things better than brighter things [1], feeling of lightness in legs [1] Dangers Can cause vasoconstriction leading to loss of extremities and organ damage [1], many people have bad trips on it [1], more dangerous than Ipomoea spp. [1] Dangerous if used foolishly [1], as dangerous as other psychoactive substances [1] Natural knowledge Large colourful flowers [3], from South America [1], looks like Datura spp. [1], from the Americas [1], from Hawaii [1], grows as a bush [1] Grows in Slovenia [2], grows in higher altitude where trees have been cut [1], beautiful berries [1] https://doi.org/10.1371/journal.pone.0245022.t008 hallucinogenic effects were reported. The individual who consumed the plant in alcoholic beverages believed it is not dangerous in alcohol, saying that this cancels out the GABA inhibiting effect that they ascribe to the plant, but that otherwise it is harmful. Artemisia spp. were the only plant or mushroom listed by one of the participants, something that was otherwise seen only for ayahuasca and Psilocybe spp. It stands out from the other two, however, as being the only one that is traditionally used in Slovenia. Pelinkovec, an alcoholic beverage made by infusing Artemisia spp. into spirits, has an extensive history of use as both a medicine and recreational beverage in some parts of the country. It is thus unsurprising to see it listed alone, though odd that it was listed so few times in total; this may be tied in with perceptions of this plant and the lack of consensus as to its hallucinogenic nature, with many likely not mentioning it as they do not believe it to be psychoactive. This topic is further addressed in the limitations section at the end of this paper.
Responses are summarised in Table 9.

Peganum harmala
From the family Nitrariaceae, this plant is from the Mediterranean region and Near East [68]. Its seeds are used medicinally for a range of ailments and the presence of the alkaloids harmine and harmaline also give it psychoactive effects [62,68]. P. harmala L. has been known to cause a dream-like state at low doses and full-blown hallucinations at higher doses, while also being able to intensify the effects of other drugs [62,68]. Its seeds are often seen as the best MAOI source outside of tropical regions and thus have been often used to make ayahuasca analogues, for example by combining it with Phalaris L. spp. [69,70]. 3 participants in the present study used this plant. Curiosity led 2 of the participants to try it, while the third used it to strengthen the effects of Psilocybe spp. This participant could not differentiate the effects of the plant from the mushrooms, though their trip started faster, hit harder, and lasted longer. The others described the effects as everything taking on a plastic-like quality. One participant stressed that as an MAOI this plant could be dangerous if combined with the wrong substances, possibly causing death; as such, they adjusted their diet to avoid foods like coffee, cheese, and chocolate before using it as they felt these would have a bad reaction with it.
Responses are summarised in Table 9.

Others
Responses are for substances listed twice are summarised in Tables 10 and 11. Responses for substances listed only once are summarised in Table 12.

Limitations
As recruitment was largely carried out through word of mouth, many participants knew each other. As such, this is not a random sample. Combined with the use of social media, this may have led towards a younger demographic being studied. Natural knowledge Pointed green leaves [2], purple flowers [1], among first plants to grow in spring [1], ginger-like rhizome [1], grows in Slovenia [1] Purple flowers [2], low and leafy [2], dormant most of year underground [2], grows in Slovenia [1], does not grow in Slovenia [1] https://doi.org/10.1371/journal.pone.0245022.t010 As with any study based on self-report, the present study is limited to assuming responses were truthful. As drugs may be a taboo topic, it may be difficult to obtain honest answers. However, individuals uncomfortable answering such questions would likely not participate. Participants were, in fact, quite eager to share their experiences and knowledge about this topic, and expressed excitement that the subject was garnering academic attention.
All plants and mushrooms that participants listed have been incorporated here even if not proven hallucinogenic, as the belief that a substance is hallucinogenic is more important in an anthropological context than its objective effects. However, participants were told in advance that marijuana use was not a focus of the study since marijuana is not traditionally grouped with hallucinogens and is only hallucinogenic in extreme doses. Additionally, its popularity would likely have skewed this study away from its focus.
Identification issues may also be present, though the participants were likely knowledgeable enough to know what they were getting and using, especially as it usually came from trusted sources. Table 11. Overview of Mimosa hostilis and changa.

Conclusion
In academia, non-problematic drug use is often ignored, with dangerous and problematic cases often being used as an archetype for all substance use; indeed, when studies focus on this aspect, they are sure to produce biased results [71]. In the present study of 68 users of hallucinogenic plants and mushrooms in Slovenia, a great deal of non-problematic drug use has been recorded. Furthermore, much of this use was even described as being beneficial in nature.
Rather than seeing all drug use as problematic, it is time for a more modern and science-based approach to replace the engrained religious-moral view that assumes all altered states of mind (or the substances that cause them) are "bad" and harmful.