Hallucinogenic drugs are typically non-addictive alkaloid chemical substances that produce in humans altered sense-perceptions or states of consciousness. More specifically, they are characterized by classes of pharmacological agents which change the subjective qualities of perception, thought and emotion. In the basic definition, there is no quantitative change in alertness/activity. In practice, however, hallucinogenic drugs may have such activity in addition to their hallucinogenic effect; very few drugs have only a single effect on the human body. As with all chemicals, whether the effect is medicinal, narcotic, or poisonous depends on the chemical and the dosage. Many such chemicals are also called "psychedelics" or "entheogens".

Table of contents
1 History of Hallucinogenic Drug Use
2 Pharmacology
3 External links

History of Hallucinogenic Drug Use

Hallucinogenic drugs are among the oldest drugs used by humankind, as hallucinogens naturally occur in mushrooms, cacti, and various other plants. Whether the use of hallucinogens is encouraged, unregulated, regulated, or prohibited, and whether hallucinogens are used for recreational, medicinal, or spiritual purposes, varies from culture to culture and nation to nation. Hallucinogen use is relatively rare in most current societies. In most countries of the world, common hallucinogens are illegal and their possession is considered a crime as of 2003. Rarely, an exception will be made for religious purposes. For example, in the United States, possession of peyote cactus is illegal for most purposes, but the cactus is legally grown and used for religious rituals among various Southwestern Native American tribes.

In contrast to most modern societies, many tribal societies actively encourage the use of hallucinogens, usually as part of a religious ritual. In others, hallucinogen use, while not exactly encouraged, is tolerated and not seen as uncommon.


Many sects of Christianity have associated hallucinogenic drug use with witches and the devil. Rumours circulated among medieval Europeans that the hallucinogen belladonna was a key ingredient of various magical flying ointments. When applied to mucous membranes, alkaloids in the plant induce (among other effects) hallucinations, nausea, and a sensation of flying. Witches were commonly believed to fly through the air on broomsticks after using the ointment. Consequently, any association with the belladonna plant could have proven extremely dangerous and lead to one's execution as a practitioner of witchcraft.

Native American use of Peyote

Peyote cactus has been used in various Native American religious practices in the Southwestern United States and Mexico since long before Europeans arrived. The ghost dance religion that developed in the 1880s among Native Americans in the region involved peyote use. Rain forest tribes in the Amazon River basin have been known to make use of various hallucinogenic plants, as well.

Most Spanish missionaries in the New World condemned the natives' use of hallucinogenic plants as the work of the devil, and attempted to eliminate the practice through forced conversion to Christianity and banning the transmission of knowledge about the plants.

Hallucinogens After World War II

In most Western societies, hallucinogenic drugs have been used for research and therapy, and perhaps some military/intelligence applications. Military and intelligence research into the potential use of hallucinogens for mind control was done in the 1950s and 1960s, under projects such as the CIA's MKULTRA program and various US Army experiments. But by far the most common use of hallucinogens in the West has been for recreational use.

LSD was first synthesized in 1937 by Dr. Albert Hofmann. The recreational use of hallucinogens, especially LSD, became popular among certain segments of the Western youth counterculture in the 1960s, led by countercultural icons such as Dr. Timothy Leary and Carlos Castaneda, who encouraged the use of LSD and other hallucinogens as a psychedelic, or mind-revealing, tool for spiritual growth and exploration.

As a result of the growing popularity of LSD, and, some contend, establishment disdain for the hippies with whom it was heavily associated, LSD was banned in the United States in 1967. Despite being scheduled as a controlled substance in the mid 1980s, Ecstasy's popularity has been growing since that time in western Europe and in the United States.

As of 2003, most hallucinogens are controlled substances in most Western countries. One notable exception to the current criminalization trend is in parts of Western Europe, especially in the Netherlands, where hallucinogenic mushrooms are considered to be soft drugs, along with marijuana. While the possession of soft drugs is technically illegal, the Dutch government has decided that using law enforcement resources to combat their use is largely a waste of time and money. Thus, public "coffeeshops" in the Netherlands openly sell hallucinogenic soft drugs for personal use (See Drug policy of the Netherlands).

This attitude has been spreading throughout Europe in the latter part of the 20th century; many European countries no longer actively pursue anti-drug policies, and rarely enforce extant legal penalties for personal-use quantities of hallucinogenic drugs. This is especially true with mild hallucinogens such as marijuana, which is rapidly gaining acceptance in western Europe as a harmless and socially acceptable intoxicant, much as alcohol is considered throughout the West.


Hallucinogens can be classified by quality of action, mechanisms of action, or simply by chemical structure. These classifications often correlate to some extent. The classification system below attempts to blend these tree approaches in order to create a balanced and simple overview that is as clear and easy to grasp as possible.

Almost all hallucinogens contain nitrogen and are classified as alkaloids. Salvia divinorum is one exception; it seems to contain the first discovered diterpene hallucinogen. Many hallucinogens often have chemical structures similar to those of human neurotransmitters, such as serotonin, and temporarily interfere with the action of neurotransmitters and/or receptor sites.

A classical classification is that of Lewin (Phantastica, 1928):
Class I Phantastica roughly correspond to the psychedelics, which is a more modern term usually used as synonym to "hallucinogen" by people with positive attitudes towards them. Here the term is used a bit differently to discriminate one particular class of hallucinogens which it seems to describe best. They typically have no sedative effects and there is usually a clearcut memory to their effects.

Class II Phantastica correspond to the other classes in this scheme. They tend to sedate in addition to their hallucinogenic properties and there often is an impaired memory trace after the effects wear off.

Pharmacological Classes of Hallucinogens, and there general subjective effects:

Commentary: Hallucinations from these dissociatves are generally only experienced in dark rooms or with eyes closed, unless at very high doses above what is normally consumed recreationally. Nitrous Oxide has very different effects however, and even at low doses includes auditory hallucinations.

  • Serotonergics (5HT receptor agonists)
    • Tryptamines
    • Lysergamides
      • LSAs/LAAs#
      • LSD, acid

  • Phenylethylamines
    • Substituted Phenylethylamines
    • Substituted Amphetamines
      • MDMA, Ecstasy
      • 4-methyl-2, 5-dimethoxyamphetamine also known as DOM or STP

Commentary: Both the tryptamines and Phenylethylamines, if they cause hallucinations, generally cause the same style of hallucinations. These include surface warping, blurriness of vision, trails, and some type of colors. Some however, are extremely powerful at recreational doses, such as DMT, these can induce hallucinations which completely block out the real world.
Anticholinergics Commentary: Anticholinergenics, are sometimes called "deleriants". These substances are the most likely to produce what is traditionally thought of as a hallucination, namely seeing a realistic looking object that is not there (as opposed to colors or distortions in vision).

  • Cannabinoids
  • Other
    • Muscimol# and Ibotenic acid#, the active constituents of fly agaric

Commentary: Although muscimol does not usually cause normal hallucinations, it has a tendency to put the user to sleep, during which the user is able to have very vivid dreams with good dream recall.

Commentary: Salvia hallucinations tend to primarily be mental, instead of an image change, the brain changes what it believes that image to be (for example, a user looking at a cup believes it is a planet).

    • Cryogenine/Vertine#, the active constituent of sinicuichi

(Those with a "#" beside them are naturally occurring.)

Hallucinogenic Plants, Fungi, and Animals

Among the most well-known hallucinogenic plants and fungi are:

  • Fly Agaric (Amanita muscaria)
  • Peyote (Lophophora williamsii)
  • Deadly nightshade (Atropa belladonna)
  • Henbane (Hyoscyamus niger)
  • Mandrake (Mandragora officinalis)
  • Marijuana (Cannabis sp.)
  • Ergot (Claviceps purpurea)
  • Thorn Apple (Datura sp.)
  • Iboga (Tabernanthe iboga)
  • Ayahuasca (Banisteriopsis caapi)
  • Floripondio (Brugmansia sp.)
  • Various coprophilic mushrooms (Conocybe, Panaeolus, Psilocybe, Stropharia)
  • San Pedro (Trichocereus pachanoi)
  • Tlitliltzin/Badoh Negro (Ipomoea violacea)
  • Ololiuhqui/Coaxihuitl (Turbina/Rivea corymbosa)
  • Epená (Virola sp.)
  • Pipiltzintzintli/Diviner's Sage (Salvia divinorum)
  • Nutmeg (Myristica flagrans)
  • Sinicuichi (Heimia salicifolia)

Among the most well-known hallucinogenic animals are: See also:

External links


Science & Consciousness Review, The Neurochemistry of Psychedelic Experience: http://www.sci-con.org/editorials/20030603.html