a data driven anthropological research on drugs

The user-based online organization Erowid aims to provide unbiased information about a broad variety of psychoactive substances. Their website provides pharmacological, chemical, biomedical and botanical resources, and hosts more than 20.000 experience reports written by drug users. This large body of user-based knowledge is frequently consulted by drug users who wish to reduce the harmful effects of drug consumption, and whose primary source of information is more and more online.

In order to understand the knowledge practices associated with Erowid, and their entanglements with contemporary drug use, our team of digital anthropologists explored novel methods to analyze Erowid's digital content and connect it with ethnographic expertise. The results that we present on this website provide both a glimpse into practices of reporting drug use, into actual patterns of drug consumption, and into the possibilities of a digitally literate anthropology.

Dataset description


From a total of 20,534 reports, we consider for the following analysises only the ones concerning a selected set of substances. Reports mentioning the selected subset of substances constitute roughly the 45% of the full dataset available on

in: 9,480 9,480 reports mention one of the selected substances 11,282 reports do not mention one of the selected substances

Dataset breakdown per substance


The visualization shows the number of reports mentioning one of the selected substances at least one time. On a total of 10,387 reports, the biggest amount is related to hallucinogenics (7375), followed by stimulant substances (1340) and sedatives (1343). The smallest amount of reports are related to nootropics and supplements (329).

Users demographics


The visualization presents some general statistics about users reporting experiences. More than 9,000 users have reported their body weight, with the average weight being 70 kg. Only 969 users have declared their age. The average age of users is 23. 9,683 reports out of 11,187 are from users who have declared their sex. A gender issue emerges from the analysis as there are 8,348 reports from male users , and only 1,335 from female users . Interestingly, Cocaine and MDMA have a relatively higher female percentage than all the other substances. Looking at the age distribution we can see that all substances are reported by younger users (below 25 years old), but with a deeper observation two groups can be identified. Amphetamines, AMT and H.B. Woodrose are are exclusively reported by users below 35 years old while substances like Cocaine, DXM and MDMA have a wider age distribution.

Most used word pairs per substance


The text of each report has been mined in order to extract relevant language connected to a particular substance that might provide deeper insight into frequent experiences with this substance. The visualization shows the top 30 word pairs (bigrams) for each substance and how often they occur in a subset of reports. Each substance has its own vocabulary. Actions, tools, effects on the body, dosage, suggestions of consumption, persons and groups emerge in different amounts from different substances

Substances' usage network


This network of co-consumption shows which substances are frequently consumed together and thus appear in the same experience report. The visualization allows to explore consumption behavior and shows clusters of substances. The bigger a node, the more often the substance is mentioned. The thickness of the connecting line and the closeness of two nodes provide information about how frequently two substances are co-consumed. Clusters of substances that are frequently consumed together are colored with the same shade of gray. You can explore the network by zooming in and out, searching for a substance, or selecting a node for more information. When clicking on a node, a list of co-consumed substances is shown

Usage trends overtime


The visualization shows the co-consumption pattern of various substances over time. Only substances mentioned simultaneously in one report during at least two years are considered for the analysis. The thickness of each stream represents the total amount of co-occurences. By clicking on a substance from the list on the top, a stream graph of the substances co-consumed with it during the last fourteen years will be visualized below. It is possible to spot the rise and fall of particular substances and the bold entrance of some new drugs in the last years.

Total occurrences per substance

Distribution of dosage according to the users


For this analysis, we looked at the reported amount of the consumed substance. We were interested to discover whether the knowledge available online concerning dosage recommendations had an impact on actual dosage behavior. We expected a decrease in dosage variability over the years. From the present analysis, however, we could not verify this assumption. For each year, all users are divided in four equal groups, according to the reported dosage. Users reporting a very unusual dosage are not grouped and represented as outliers. The visualization shows if and to which extent the average dosage for a substance changes over time.

Description of analyzed substances


In this section you can find a short description for each substance mentioned in the previous analysis. The descriptions are based on the information available on



Amphetamines are a strong physical and mental stimulants that are available widely in both prescription and street forms. Their effects are very stimulating, suppressing human needs like appetite or rest which is the reason it was used in several Armies as a performance enhancer. Today it often times comes in its prescription form Ritalin and Adderall.



A designer drug that produces hallucinogenic effects paired with euphoria. Side effects can include vomiting and nausea.


Banisteriopsis caapi

A powerfully psychedelic, traditionally used as a spiritual medicine in the indigenous Amazon. It contains a mixture of MAOI and DMT that allow the DMT to be orally active in the human body. Ayahuasca produces extremely intense visions and insights, combined with a form of purging. These effects are used as medicinal properties amongst the shamans of the Amazon.



One of the most popular stimulants worldwide. It derived from the Erythroxylum coca plant and can produce stimulating and euphoric effects. Cocaine can also be highly addictive.



A very strong psychedelic which is short-acting when being smoked, producing intense visions. Since it is produced in many plants, animals and the human body, it is not orally active. However, in combination with an MAOI, it is also part of the indigenous medicine Ayahuasca.


dextromethorphan hydrobromide

Used as a cough suppressant, DXM is a available over-the-counter. When taken in very high dosages, it produces strong dissociative effects, similar to Ketamine.


Gamma butyrlactone

A precursor to GHB that produces very similar effects that come and go more rapidly. GBL is also acidic and has to be watered down if consumed as a drug. The effects and the side effects are more extreme than with GHB which makes it even more difficult to handle.



A GABA-based neurotransmitter that is part of the human central nervous system. It is used as a medication for instance to treat narcolepsy. Used as a drug, it produces short acting alcohol like intoxications that makes GHB popular as a party drug. Due to its sexual stimulating effects it is also very popular amongst MSM (Men who have sex with men) populations. GHB is very hard to dose and especially in combination with alcohol, it can lead to a long lasting coma-like state (‘G-sleep’) or even death. When used over long periods of time, it can also cause forms of psychological and physiological addiction.

Ha·wai·ian ba·by wood·rose

Argyreia nervosa

The seeds contain the psychedelic substance LSA.



The first and still very popular ‚nootropic‘ or smart drug that is said to induce cognitive enhancement.



Originally a medication to treat narcolepsy, Modafinil is also used as a cognitive enhancement drug that is said to increase focus and wakefulness.



Melatonin is a hormone produced by the pineal gland and involved in the regulation of sleep. It is used as a sleep aid and to help reset the body's clock and help reduce jet-lag.

Morn·ing glo·ry

Ipomoea violacea

A psychedelic plant that contains LSA, a naturally occurring relative of LSD. It has a long history of traditional use as a medicine amongst indigenous tribes in Mexico.



Ketamine is a dissociative drug that has a history in veterinary and human anaesthetics. In low dosages it produces ‘fluffy’ sensations which can transform into dissociation of the consciousness in higher dosages (‘K-Hole’). Ketamine is widely used as a party drug.


Mitragyna speciosa

It has a long history of use in Thailand and South East Asia. The leaves are chewed as an opiate substitute and stimulant, primarily among the working class.

Laugh·ing gas

nitrous oxide

Nitrous Oxide is an anaesthetic that is also used in dentistry. It is also used as a whipped cream propellant which makes it highly available. Its effects are short lasting and dissociative, similar to DXM or Ketamine.



LSD is the best known and most researched psychedelic in the western sciences. Discovered in 1943 by Swiss biochemist Albert Hofmann, the substance produces pseudo-hallucinations, synesthesia and in higher dosages phenomena like ‘ego-death’ and mystical experiences.


3,4-methylenedioxymethamphetamine; XTC

MDMA is one of the most popular synthetic drugs, especially in Western countries. It is either sold in crystalline form (‘Molly’, MDMA) or as the main ingredient in XTC (‘Ecstasy’) pills. It produces strong empathogenic, euphoric, and stimulant feelings. The emotional openness which it produces makes it popular in the electronic dance music scene but also interesting as a tool psychotherapy.


Psilocybe mushrooms

Many species contain the psychedelic chemicals psilocybin or psilocin. They have a long history of use in Mexico and are currently one of the most popular and commonly available natural psychedelics. Their effects are very similar to LSD, including pseudo-hallucinations and profound insights or realizations.


Myristica fragrans

Produces deliriant effects when used in large quantities. It has a history of use from the Arabian Peninsula to South East Asia.

Sal·via di·vi·no·rum


Its leaves contain the extremely potent Salvinorin A. It has a long history of use as spiritual medicine amongst the Macatecs in Mexico. Since the mid 1990s it became widely available and popular despite the fact that its hallucinogenic effects are considered unpleasant by many people.

Syr·i·an rue

Peganum harmala

Its seeds contain harmine and other harmala alkaloids that act as a MAO-A inhibitor which potentiates and prolongs the effects of other drugs, especially psychedelics. It is one of the plants that is speculated to be the ancient Soma (India) or Haoma (Persia).