DMT (N,N-Dimethyltryptamine)


1. Overview
2. Chemistry
3. History
4. Ingestion
– 4.1 Dosage
– 4.2 Ayahuasca
– 4.3 Changa
5. Effects
– 5.1 Intensity Scale
6. Botany
7. Legality

1. Overview

N,N-Dimethyltryptamine (‘DMT’) is a potent psychoactive tryptamine compound with a long history of shamanistic use. Its presence is widespread throughout the plant and animal kingdom and trace amounts appear endogenously in humans (putatively as a neurotransmitter, though its exact role is unclear). When ingested by smoking, insufflation, or injection (intravenous/intramuscular), the effects are both short-lived (peaking within 20 minutes and lasting up to 1 hour) and extremely intense.

DMT is not orally active in humans without the co-ingestion of a monoamine inhibitor (‘MAOI’), e.g. the harmala alkaloids found in Banisteriopsis caapi and Syrian Rue. MAOIs temporarily inhibit MAO-A, preventing the destruction of monoamines. In the presence of an MAOI, orally administered doses of DMT generate longer lasting, less ineffable, and more personal trips (with an onset of roughly 30 minutes, a peak around 2 hours, and a cessation of psychoactivity within 6 hours). This is the mechanism behind ayahuasca and cognate brews. However, MAOIs also prolong and potentiate DMT when ingested by other means, too – e.g. smoking/vaporization – and this is the mechanism behind changa.

Note: Oral ingestion of MAOIs requires caution and knowledge of the adversely interacting substances (e.g., stimulants and SSRIs). For more guidance, see our safety section on MAOIs.

Warning: DMT experiences can be overwhelmingly intense. Trips are often ineffable, inscrutable experiences, defying ordinary comprehension. As such, they can be very difficult to integrate, and only those with stable mental conditions would consider approaching the substance. It is by no means for everyone. We also inform the reader that the compound, once extracted from a natural material, is illegal internationally.

2. Chemistry

SpiceCrystal001 (1)

DMT crystal

DMT was first synthesized in 1931 by Richard Manske, when it was isolated as the N-oxide from Anadenanthera peregrina seeds (the alleged source of Piaroa snuff). Its discovery as a natural compound is credited to Oswaldo Gonçalves de Lima, who in 1946 isolated an alkaloid he called ‘nigerine’ from the root bark of Mimosa hostilis. We now know that de Lima’s findings were imprecise, as the empirical formula he recovered ascribed an oxygen atom to the compound. Less controversial was the identification of DMT in 1955 as found in the seeds and pods of Anadenanthera peregrina. DMT has since been found in a plethora of diverse organisms. It is present in over 50 plant species and 4 animal species.

Psychoactively, it is an agonist of serotonin receptors 5-HT2A, 5-HT2c and 5-HT1a. As with classical hallucinogens such as psilocybin, LSD, and mescaline, much of DMT’s psychedelic effects can be attributed to a functionally selective activation of the 5-HT2A serotonin receptor. However, DMT has stronger efficacy at the human serotonin 2C receptor than at the 2A receptor, so the former may also play a role in explaining its psychoactive character.

Though DMT is in many ways best handled and stored as a fumarate, psychonauts generally prefer DMT in freebase form, since whilst it is less stable than DMT fumarate, it has a lower boiling point and so is easier to smoke/vaporize. In solution, DMT degrades quickly and should be protected from air, light, and heat (in a freezer) when stored. Freebase DMT (C12H16N2) has the appearance of white/translucent crystals. Its melting point hovers between 44°C and 68°C. It has a molecular weight of approximately 188.26884 g/mol.

3. History

The earliest archaeological discovery of DMT use dates back to the late 8th Century AD, at a burial site in Northern Chile. Here, a bag with snuffing paraphernalia was found with residue of DMT, 5-MeO-DMT, and Bufotenin. Much later, Jonathan Ott, in Shamanic Snuffs or Entheogenic Errhines (2001), notes that in 1496 Friar Ramon Pane documented the use of yopo snuff among the Taino of what is now Haiti/Dominican Republic. We know now that yopo was produced from the seeds of Anadenanthera peregrina, which contains DMT, 5-MeO-DMT, and Bufotenin. In the 16th Century, up to the 19th Century, the Cohoba communities – and those along the Rio Guaviare – of Colombia made snuff from the yopo tree. The use of yopo in Venezuala has also been documented around this time.

Though DMT had been synthesized in 1931, it was not until 1955 that N,N-DMT was identified as a naturally occurring compound, and as a principal component of the Anadenanthera peregrina seeds used by the Cohoba. Its psychoactive status was verified by Steven Szára in 1956. In 1965, Jacques Poisson isolated DMT from leaves of Diplopterys cabrerana provided by Aguaruna Indians. The first identification of DMT in Psychotria viridis was made in 1970 under the lead of Ara der Marderosian, after obtaining leaves of the plant from the Cashinahua Indians. (Der Marderosian’s was the first published investigation in which DMT was recognized as a psychoactive component of ayahuasca (as prepared by the Cashinahua).)

In 1971, under the UN Convention on Psychotropic Substances, DMT became a schedule 1 drug internationally, meaning that its use is restricted to scientific and medical research. However, organic materials containing DMT are not themselves regulated under the convention.

On the rich history of the ayahuasca brew, see ayahuasca.

4. Ingestion

DMT crystal at 400x magnification

DMT can be smoked, vaporized, injected, insufflated, taken anally, or administered orally in conjunction with an MAOI. Each of these methods of ingestion require different preparatory work and doses. Users are advised to start with very low doses and raise gradually as desired.

Due to the unpredictability of the effects, unfamiliar users are strongly advised to ingest in the presence of a sitter: someone trustworthy and warm who can make sure the user is safe. It is extremely unlikely that smoking DMT would lead to a dangerous overdose since the onset is so rapid that one could only take in a safe amount before entering a ‘hyperspatial state’, without being able to smoke more until one returns. However, the increased heart rate and blood pressure could mean that those with heart conditions or similar serious ailments may be put at risk through an intense experience. Consult your doctor if you are unsure. Because effects are unpredictable and some have been known to black out and to drown or otherwise seriously injure themselves, caution is necessary, and a safe environment.

DMT is not physically addictive. Given the nature of the experience, most will find that they can reliably self-regulate their use. But if you do find yourself investing more emotional energy in ‘hyperspace’, you should reduce or cease your usage. If you find yourself experiencing problems with trip integration, mental or emotional distress as a result of your DMT usage, stop using immediately. If problems persist, seek professional guidance.

Note: DMT is not the same as 5-MeO-DMT nor 5-OH-DMT (Bufotenine). 5-MeO-DMT is a much more potent psychotropic (perhaps 4 times stronger), with different characteristics to DMT. Bufotenine, except in trace amounts, is to be avoided: it causes anxiety, sweating, nausea, circulatory distress, skin flushing, yellowed vision, and can be lethal in relatively small doses.

4.1 Dosage

Users may typically take doses in the following regions (‘mg/kg’ = mg of DMT per kg of user’s body weight):

As always, dosage advice must be taken with caution. Because of the number of variables involved in judging the potency of psychedelic substances (e.g., the purity of the substance, the temperature at which the substance is smoked, the background brain chemistry of the user, the user’s level of physical tolerance, etc.), it is not possible to give sound advice that covers all circumstances, and we cannot be held responsible if the information below is incorrect or the cause of harm should anyone decide to reconstruct practices noted here for research purposes – we do not advise or endorse ingestion of DMT.

Smoked (freebase): 25mg – 70 mg
Threshold dose: approx. 0.5mg/kg
Breakthrough dose: approx. 0.7mg/kg

Vaporized (freebase): 15mg-60mg
Threshold dose: approx. 0.35mg/kg
Breakthrough dose: approx. 0.5mg/kg

Intravenous (freebase): 10mg-40mg *
Threshold dose: approx. 0.2mg/kg *
Breakthrough dose: approx. 0.4mg/kg *

Insufflation (freebase): 60mg-120mg
Threshold dose: approx. 0.35mg/kg
Breakthrough dose: approx. 0.5mg/kg

Oral (with MAOIs): 40-160mg.
Note: this varies greatly depending on individual metabolism, etc. New users would, it is said, be wise to start with no more than 60mg.

Oral ingestion of Mimosa hostilis inner rootbark (with MAOIs): 1-3 grams.

Oral ingestion of Psychotria viridis/’Chacruna’ (with MAOIs): 40-160 grams.

Oral ingestion of Diplopterys cabrerana/’Chaliponga’ (with MAOIs): 2-8 grams.

* Intravenous injection of DMT is not recommended, for two reasons:

  1. The only official research into IV-administered DMT (by Strassman) used FDA-approved pure DMT fumarate. The quality of home extractions is always questionable, and one may have solvent traces and other impurities that could be uncomfortable, painful or highly dangerous to inject.
  2. The onset of the effects are so quick that one might not be able to take out the needle in time and end up accidentally ripping their vein out while in hyperspace, or putting it down too near and rolling around and otherwise injuring oneself.

If users were to insist on trying this method of ingestion, they are advised to ensure they have made many purification steps and making sure it no solvents or other chemical traces are present (e.g., redissolving the recrystallized product in USP grade acetone). In addition, take at most 0.2mg/kg. Most importantly, have a sitter present.

4.2 Ayahuasca/Pharmahuasca

(See ayahuasca.) The mechanism behind ayahuasca brews is most often the combination of a plant containing N,N-Dimethyltryptamine (DMT) and a plant rich in harmala alkaloids (an MAOI), traditionally B. caapi vine. MAOIs are needed in order for DMT to become orally active. Though ayahuasca has historically been prepared with Justicia pectoralis in place of a DMT-component, DMT incarnations of the brew will be the topic of this section. ‘Pharmahuasca’ refers to a variant on ayahuasca in which one of the two roles (DMT component or MAOI) is played by a pharmaceutical drug or extracted freebase compound, as opposed to a natural plant material.

Peruvian Ayahuasca

Peruvian Ayahuasca

Ayahuasca experiences set in roughly half an hour after consumption, peak after two hours, and generally last under six hours. Subjectively, users often report spiritual revelations concerning the nature of the universe as well as deep, personal epiphanies as to how they can be a better person. Physiologically, ayahuasca increases both heart rate and diastolic blood pressure. Vomiting and diarrhoea are common. In some cases, individuals experience considerable psychological stress during the experience. Extreme caution should be taken by those who are at risk of heart disease, and it would be wise to avoid the substance if one is, in one way or another, psychologically unstable.

DMT-containing plant materials commonly used for oral ingestion:

Diplopterys cabrerana: 2-8g
Mimosa hostilis (inner rootbark): 1-3g.
Psychotria viridis (leaves): 40-160g

MAOI plant materials commonly used for oral DMT ingestion:

Banisteriopsis caapi (vine): 40-120g
Syrian Rue (seeds): 2-5g

For more on traditional preparation, dosage, and techniques, see here.

4.3 Changa

Smoking changa is preferred by those who like a prolonged experience (twice as long in some cases) with a slower onset, and who want to bring more back from the trip. Users often find that changa methods yield a more personal, intimate, shamanic adventure, though perhaps not to the extent of an ayahuasca experience.

Changa is composed of freebase DMT and harmala alkaloids jointly infused into an organic smoking blend. It is usually smoked in a bong or pipe. It can also be smoked in a joint (often a weaker ratio with harmalas 3:1 is smoked this way for a mellower experience, or at least a gentler breakthrough and slower comedown).

Crystallized DMT ('spice')

Crystallized DMT (‘spice’)

One can get harmalas and smoke material from the Banisteriopsis caapi leaf. The basic ratio is 1:1 – that is, 1g pure harmalas, 1g spice (freebase DMT), and 1g of leaf matter in which to infuse the harmalas and spice. (Remember: smoked, this would give enough for around 20-25 ‘breakthrough’ experiences.) This means the infused leaf, when dried, will weigh 3g. In place of pure extracted harmalas, users sometimes carry out the following procedure. 10g of caapi leaf are added to a pot with hot water and simmered gently for a few hours. New water is occasionally added to maintain the level. The leaves are removed and excess water squeezed into the pot. The user then evaporates and reduces all of the liquid, before scraping the residue. This powder is added to 1g of caapi leaf to make 1g of 10x enriched caapi leaf.

To make the changa, 99% IPA is used for infusion. 40ml of IPA is poured into a small glass and heated up in a pot of water (i.e. double boiler method). The IPA need only be very warm, not piping or boiling hot. Once this temperature is reached, the user removes the glass from the pot and dissolves the 1g spice in it. They then place the 10x enriched 1g Caapi leaf on a small dish and pour over the IPA solution, mixing well. This dish is then placed in a cool area with a fan blowing over it until fully dry. It is dried until it can be dried no more.

5. Effects

The principal physiological effects of DMT-ingestion include an increased heart rate, increased blood pressure, strong dilation of the pupils, and steady breathing. The user will appear to be in a trance. On the psychological effects, an extract from Strassman (1996):

“Psychological effects began nearly immediately during the DMT [intravenous] infusion, peaked within 2 min, and usually were completely resolved within 30 min. The higher doses of DMT produced a rapidly moving, multi-dimensional, kaleidoscopic display of intensely colored abstract and representational images. Auditory effects were less common, and were not frank hallucinations. Transient anxiety was common, but usually quickly became replaced by euphoria. Dissociation of awareness from the physical body was common, as were later feelings of alternating heat and cold. The higher dose effects completely replaced ongoing mental experience, and usually was described as more compelling and convincing than ‘ordinary’ reality or dreams. Lower doses (0.1 and 0.05 mg/kg) primarily affected physical and affective functions, with little perceptual disturbances.”

An extract from Terence McKenna’s Food of the Gods (1999):

“The experience that engulfs one’s entire being as one slips beneath the surface of the DMT-ecstacy feels like the penetration of a membrane. The mind and the self literally unfold before one’s eyes. There is a sense that one is made new, yet unchanged, as if one were made of gold and had just been recast in the furnace of one’s birth. Breathing is normal, heartbeat steady, the mind clear and observing. But what of the world? What of incoming sensory data?

Under the influence of DMT, the world becomes an Arabian labyrinth, a palace, a more than possible Martian Jewel, vast with motifs that flood the gaping mind with complex and wordless awe. Color and the sense of a reality nearby pervade the experience. There is a sense of other times, and of one’s own infancy, and of wonder, wonder, and more wonder. It is an audience with the alien nuncio. In the midst of this experience, apparently at the end of human history, guarding the gates that seem surely to open on the howling maelstrom of the unspeakable emptiness between the stars, is the Aeon.

The Aeon, as Heraclitus presciently observed, is a child at play with colored balls. Many diminutive beings are present there—the tykes, the self-transforming machine elves of hyperspace. Are they the children destined to be father to the man? One had the impression of entering an ecology of souls that lies beyond the portals of what we naively call death. I do not know. Are they the synesthetic embodiment of ourselves as the Other, or of the Other as ourselves? Are they the elves lost to us since the fading of the magic light of childhood? Here is a tremendum barely to be told, an epiphany beyond our wildest dreams. Here is the realm of that which is stranger than we can suppose. Here is the mystery, alive, unscathed, still as new for us as when our ancestors lived it fifteen thousand summers ago. The tryptamine entities offer the gift of new language; they sing in pearly voices that rain down as colored petals and flow through the air like hot metal to become toys and such gifts as gods would give their children. The sense of emotional connection is terrifying and intense. The Mysteries revealed are real and if ever fully told will leave no stone upon another in the small world we have gone so ill in.”

Callaway (1999) administered doses of ayahuasca with the following average alkaloid content: 35.5mg DMT, 252.3mg harmine, 29.7 harmaline, 158.8 THH. The subjective effects of the experiment were as follows:

“…peak plasma levels of DMT were associated with intricate and colored eyes-closed visual imagery, complex thought processes, and a general state of heightened awareness”. “…overall perceptual, cognitive, and affective processes were significantly modified while maintaining the presence of a clear sensorium”. Nausea, vomiting, and diarrhoea were common, with one subject vomiting only 45 minutes after ingesting the tea. One researcher reported intense fear. Nystagmus and tremor were also observed in some.

A detailed interpretation of the entities and realms typically encountered (from machine elves and archangels to hyperspatial planes) can be found here.

5.1 Intensity Scale

(The following scale applies primarily to freebase DMT smoked, vaporized, or injected. When orally ingested, as in ayahuasca, experiences last up to 6 times longer and differ in character. See ayahuasca for a corresponding intensity scale.)

'Oversoul', by Alex Grey

‘Oversoul’, by Alex Grey

0-1 — Effects are slight. One might feel marginally different, perhaps more relaxed, comforted, and warm.

2-3 — Effects are more physiological than mental. Users feel bodily sensations of excitement and tension, but barely any perceptual or emotional changes are present. In Strassman’s (1996), a subject receiving 0.1mg/kg intravenous remarked, “You’ll never sell this dose. It has all of the physical effects without any of the mental ones”. Pupils dilate, tingling kinaesthetic sensations may be present, one may tremble, one may feel slightly nauseated or light-headed, and both heart rate and blood pressure are elevated.

4-5 — This is the threshold dose level for hallucinogenic effects. Visual hallucinations are common (particularly with eyes closed); auditory hallucinations somewhat rarer. One feels the same hallmark DMT ‘rush’ as at higher doses, but the experience reaches a lower plateau. An experience at this level is less frightening and mind-blowing than further levels, whilst generating sufficient perceptual and emotional effects to be interesting, novel, and pleasurable. CEVs may be intensely beautiful, deeply colored, and kaleidoscopic.

6-7 — One experiences striking eidetic phenomena and hallucinations, but one does not ‘break through’ to the critical ‘hyperspatial’ level. Perceptual distortions (largely visual) feature (perhaps moving) geometric shapes, fractals, coloured patterns, aztec/oriental motifs, faces and masks, and these may be attributed with deep emotional content. Colors are brighter, more intense, and more deeply saturated than any colors seen in ordinary waking consciousness.

8-9 — This is the ‘breakthrough’ level. The intensity and speed of the onset at this dose is overwhelming. From his experiments on subjects at this level (0.4mg/kg intravenous), Strassman (1992) writes:

“All described an intense, rapidly developed, and generally transient anxiety-provoking “rush” throughout their body and “mind.” This was described as a “freight train” by several subjects. It immediately and totally disrupted normal mental function, replacing it with the hallucinogenic effects of DMT. Most subjects lost awareness of their bodies at this point, and many were not cognizant of being in the hospital, or participating in an experiment, so completely compelling, arresting and overwhelming were the initial two minutes of the experience. Interestingly, the three subjects with experience smoking DMT free base all described the effects of the [intravenous] drug as more overwhelming and rapid in onset than the smoked form.

Visual effects, at the peak, included concrete, formed, more or less recognizable visual images with eyes open or closed. Examples of these types of images are: “a fantastic bird,” “a tree of life and knowledge,” “a ballroom with crystal chandeliers,” human and “alien” figures (such as “a little round monstrous creature with one big eye and one small eye, on nearly invisible feet”), stairways, etc. At the other end of the visual effects spectrum, some subjects described kaleidoscopic geometric patterns that were not obviously representational. In between these two poles were discrete visual images of novel phenomena. For example, some subjects saw “the inside of a computer’s board,” “tubes,” “ducts,” “DNA double helices,” “a pulsating diaphragm,” ” a spinning golden disc off to my left,” ” a huge fly eye bouncing in front of my face,” etc. Subjects generally described the colors as brighter, more intense and more deeply saturated than any colors they had ever seen in normal consciousness, and some found the visual images more intensely constituted than those seen on other hallucinogenic drugs. […] As the effects resolved, subjects would open eyes and note that the visual field was overlaid by geometric patterns, with undulating movement and intensification of colors of external objects.

Auditory effects were consistent from one high dose to the other, if they were noted at all. Auditory hallucinations were not formed (e.g., music or voices) but were usually high pitched, “whining,” “chattering,” “crinkling/crunching,” or at times comical, such as the “boing, sproing” sounds heard in cartoons.

Somaesthetic effects were generally of a highly stimulating “fear response” nature, although all subjects recognized a curious distinction between their physical reaction to the drug and the less emotional subjective response to this reaction. Phrases such as “my body was afraid but I wasn’t” were relatively common. As effects resolved, the physical sensations became quite pleasant and relaxing. However, one subject, the least experienced of the group, began to uncontrollably shiver during the resolution phase of his non-blind high dose. This responded to verbal reassurance and brief massage of his chest and abdomen. Some subjects described a sexual effect of the highest dose; a hot and pleasurable sensation developing in their genital area. No subjects experienced orgasm or ejaculated.

Emotionally, most subjects were initially anxious as the “rush” developed. However, they quickly settled into the experience within 15-30 seconds post-injection. The majority of subjects described the high dose as exciting and uplifting, euphoric and highly positively charged. These qualities were often associated with the visual hallucinatory display. However, most paradoxically also described the emotional “valence” as “bland,” “unemotional,” and “journalistic” in nature. That is, the experience developed and resolved so quickly that there did not seem to be time for subjects to react to it one way or the other; subjects just “held on” and dispassionately watched the experience unfold. For some, however, the rapidity of the experience was not the primary reason for a lack of emotional response: one subject “tried to get myself worked up over what I was seeing, but I just wasn’t able to respond emotionally.” Some, however, found the experience emotionally quite unsettling. For example, a non-practicing Catholic found himself “face to face with God,” and “saw how insignificant and stupid mankind is, and how non-moral and basically uninterested God is.” He was “blown away; my foundation for religion has been destroyed.” He subsequently began an interest in and practice of another, non-Western religion, that “fit my needs more realistically.”

Cognitively, most subjects found the high doses to not necessarily be “novel” or “insightful.” Only a few emerged from the intoxication with new perspectives on their personal and/or professional lives (as in the subject described in the preceding paragraph). Neither was there much distortion of normal thinking processes. Subjects almost uniformly remarked at how unchanged their thinking processes were. Some subjects compared this phenomenon to that of a dream; in which their total involvement and belief in the certainty of what was unfolding coincided with an unimpaired ability to observe.

Nearly every subject found the high dose to cause an almost total loss of control. They felt extremely regressed, more or less completely helpless and unable to function either physically or psychologically in a normal manner. They did not seem able to affect the hallucinatory phenomena in any way during the earliest stages.”

Another user writes:

“As I exhaled I became terribly afraid, my heart very rapid and strong, palms sweating. A terrible sense of dread and doom filled me — I knew what was happening, I knew I couldn’t stop it, but it was so devastating; I was being destroyed — all that was familiar, all reference points, all identity — all viciously shattered in a few seconds. I couldn’t even mourn the loss — there was no one left to do the mourning. Up, up, out, out, eyes closed, I am at the speed of light, expanding, expanding, expanding, faster and faster until I have become so large that I no longer exist — my speed is so great that everything has come to a stop — here I gaze upon the entire universe.”

10 — At this undesirable level, consciousness is lost.

6. Botany

DMT is present in many plants. The following list is neither exhaustive nor indicative of the amount of DMT content in the plant. The tryptamines may be present with other potentially unwanted alkaloids, so research would be needed before extracting.

Psychotria viridis

Anadenanthera colubrina
Anadenanthera peregrina
Desmodium gangeticum
Diplopterys cabrerana
Justicia pectoralis
Limonia acidissima
Mimosa hostilis
Mimosa ophthalmocentra
Phalaris acquatica
Phalaris arundinacea
Psychotria viridis

7. Legality

Anyone embarking on a DMT experience and/or extraction should be aware of the possible legal consequences of their actions. Extracted DMT (e.g. in fumarate or freebase form) is considered illegal in all the UN-bound countries. Natural materials containing DMT (e.g., Psychotria viridis) are frequently in a legal grey area, and its control will depend on country’s current specific legislation and priorities.


For further information on DMT or other entheogens visit our growing Literature page.


Works Cited

Der Marderosian; Kensinger; Chao; Goldstein. (1970). ‘The Use of Hallucinatory Principles of a Psychoactive Beverage of the Cashinahua Tribe (Amazon Basin)’, Drug Dependence, Vol. 5, pp. 7-14.

McKenna, Terence. (1999). Food of the Gods: A Radical History of Plants, Drugs, and Human Evolution, (Rider & Co: New edition).

Ott, Jonathan. (1993). Pharmacotheon: Entheogenic Drugs, their Plant Sources and History, (Washington: Natural Products Co., Kennewick).

Ott, Jonathan. (1999). ‘Pharmahuasca: Human Pharmacology of Oral DMT Plus Harmine’, Journal of Psychoactive Drugs, Vol. 31, pp. 171-77.

Ott, Jonathan. (2001). ‘Pharmapena-Psychonautics: Human Intranasal, Sublingual, and Oral Pharmacology of 5-Methoxy-N,N-Dimethyl-tryptamine’, Journal of Psychoactive Drugs, Vol. 31, pp. 171-77.

Riba, Jordi. (2003). ‘Human Pharmacology of Ayahuasca’.

Sai-Halasz, A. (1963). ‘The Effect of MAO Inhibition on the Experimental Psychosis Induced by Dimethyltryptamine’, Psychopharmacologica, Vol. 4, pp. 385-88.

Shulgin, A.; Shulgin, A. (1997). TIHKAL: The Continuation, (Berkeley, CA: Transform Press).

Strassman, Richard. (1992). ‘Subjective Effects of DMT and the Development of the Hallucinogen Rating Scale’, Newsletter of the Multidisciplinary Association for Psychedelic Studies (MAPS), Vol. 3, No. 2.

Strassman, Richard. (1996). ‘Human Psychopharmacology of N,N-Dimethyltryptamine’, Behav Brain Res, Vol. 73, pp. 121-124.