Psychoactive Plants

views updated

Psychoactive Plants

Compounds in some plants can have an overwhelming effect on the central nervous system. Plants containing those compounds are thus known as mind-altering (active) or psychoactive plants. Their effects may be separated into hallucinogenic, stimulating, or depressing properties depending on the plant used and the present compounds, which are usually secondary metabolites. A few plants, however, have major multiple effects based on one or more compounds present, such as tobacco containing nicotine, which can be both stimulating and depressing.

Three points are worth keeping in mind about these plants. First, psychoactive drugs have been used in many cultures throughout human history. Their use has often been highly ritualized (especially true for hallucinogens) and incorporated into religions or mystical ceremonies in such a way that the novice is guided and protected by more experienced members of the ritual. Such practices have tended to minimize the potential for abuse inherent in psychoactive drugs. Second, variations in the concentrations of the active ingredients in plants make the dosing of psychoactive drugs more art than science for even the most experienced user. Last, most of the substances discussed are illegal to possess or use in the United States or Canada.

Plants Having Hallucinogenic Effects

Most hallucinogens are plant secondary metabolic compounds. In amounts that are nontoxic, hallucinogens produce changes in perception, thought, and mood without causing major disturbances of the autonomic nervous system (the system regulating the activity of the heart, smooth muscles, and glands). The psychic changes and abnormal states of consciousness induced by hallucinogens differ from ordinary experiences. Hallucinogenic users forsake the familiar world and, in full consciousness, embrace a dreamlike world operating under different standards, strange dimensions, and in different times. These compounds are a means of escaping from reality as it is commonly understood. They are not physically addicting, although dependency may develop. A few examples are provided to illustrate these properties.


The aboveground part of the cactus peyote (Lophophora williamsii, family Cactaceae) is chewed or a decoction (boiled in water) is drunk. Ingestion produces nausea, chills, and vomiting, and in most users anxiety and a dislocation of visual perspective. These symptoms are followed by a clarity and intensity of thought, the motion of brilliant-colored visions, and an exaggerated sensitivity to sound and other sense impressions. Activity is centered around the alkaloid mescaline.

Nutmeg and Mace.

Powdered nutmeg or mace (Myristica fragrans, family Myristicaceae) is taken orally in hot water or sniffed. Unpleasant side effects almost always occur, and include headache, dizziness, nausea, sickening hangovers, and tachycardia (rapid heart beat). There are feelings of detachment, visual and auditory hallucinations, and sensations of floating or flying and separation of limbs from the body. The latter typifies the more toxic hallucinogens, and the volatile oils elemicin and myristicin are thought to be involved.


The bark of the woody vine Ayahuasca (Banisteriopsis caapi, family Malpighiaceae) often together with leaves of certain Psychotria spp., is boiled and the decoction drunk in many parts of tropical South America as a major hallucinogenic beverage. Shortly after ingesting, vomiting occurs, feelings of cold and spiral-flying sensations associated with nausea take place, and visions of blue-masked specters (often assuming grotesque forms) and alarming animals (e.g., boa constrictors) are seen. During this time, hearing is distorted and the individual becomes acutely sensitive. Later, motor coordination is reduced to staggering, the body is hot and sweaty, and salivation and spitting are continuous. If sufficient active compounds have been absorbed, the sensation of flying occurs while observing beautiful and often spectacular sights, a time when exultation sweeps the body, and all physical discomforts are forgotten. Objects and scenes are vividly colored in bright but natural colors. Very few participants reach the ultimate in psychoactive experience, reported telepathic sensitivity. The active ingredients include N, N-dimethyltryptamine (DMT) and the alkaloids harmine, harmaline, and others.


The morning glories Ololioqui (Ipomoea violacea and Rivea corymbosa, family Convolvulaceae) are associated with Aztec and other Mexican Indian divinations and human sacrifices. Ingesting infusions and decoctions from powdered seeds induces delirium, hypnotic effects, and heightened visual perception. D-lysergic acid amide is the active hallucinogen.

Angel's trumpet and jimsonweed.

Ingesting or smoking the seeds, flowers, and leaves of Angel's trumpet and jimsonweed (Brugmansia spp. and Datura spp., respectively; family Solanaceae) will severely intoxicate the user, resulting in fever, flushing, dilated pupils, fast heart rate and pulse, and sometimes aggressive and violent behavior. In addition, a state of confused delirium may occur, which can be dangerous to the individual if not restrained. The usual hallucinations appear as a parade of material objects, sports cars and flowers, for example, in their simple colors. The vision-inducing hallucinogens are tropane alkaloids, particularly scopolamine.


Smoked or ingested, the resin from floral and leaf glands of marijuana (Cannabis sativa, family Cannabaceae) can cause visionary hallucinations that are often pleasant, with sexual overtones. Its most universal effect is as an euphoric, the user having a feeling of well-being and exaltation. Dangers resulting from heavy smoking exist to bronchial tracts and lungs, and prolonged use can cause personality changes that may lead to a marked deterioration in what is normally considered good mental health. The active compound is one or more resinous tetrahydrocannabinols.

Plants Having Stimulating Effects

Stimulants have long been enjoyed by humans, for they give a sense of well-being and exhilaration, self-confidence, and power, and they alleviate fatigue and drowsiness. For most, depending on the dose, there is a price to be paid for their use: increased agitation, apprehension, and anxiety, mild mania (flight of ideas), as well as increased tolerance and often dependency. All of the stimulants described next have these positive and negative effects, except tobacco.


Native to and widely cultivated in the Andes of South America, the coca plant (Erythoxylum coca, family Erythroxylaceae) has a long history of use as a stimulant and hunger depressant. Stimulation is due to the tropane alkaloid cocaine found in leaves that are chewed or ingested as a beverage. Cocaine is readily extracted from leaves and the pure compound can be sniffed, smoked, or injected. Addiction to cocaine as a recreational drug is widespread.

Chat or Khat.

Widely found native of the highlands of northeastern Africa and the adjacent Arabian peninsula, chat or khat (Catha edulis, family Celastraceae) is also cultivated in these regions. Chat leaves are chewed fresh, giving varying degrees of exhilaration and stimulation. The active ingredient is the alkaloid cathinone, and to lesser degrees norephedrine and norpseudoephedrine derived by enzymatic reduction from the unstable cathinone. Dependency on chat is common.

Coffee, Tea, Chocolate, and Holly.

Coffee (Coffea arabica, family Rubiaceae), tea (Camellia sinensis, Theaceae), chocolate (Theobroma cacao, Sterculiaceae), and holly (Ilex paraguariensis, Aquifoliaceae) are stimulating beverages common throughout the world. All possess one or more of the xanthine alkaloids: caffeine, theobromine, and theophylline. Of the three, caffeine is the most stimulating.


Tobacco (Nicotiana tabacum, family Solanaceae) leaves are smoked or chewed to act as a stimulant, depressant, or tranquilizer. Tobacco with the addictive alkaloid nicotine is perhaps the most physiologically damaging substance generally used by humans. Its use is a direct cause of lung and other cancers, coronary artery disease, and emphysema.

Plants Having Depressant Effects

By depressing the central nervous system, a number of secondary metabolites produce the effects of euphoria and well-being with sedation, including calming and tranquilizing, followed by sleep. Coma ending with death from respiratory failure can result as drug doses increase to higher levels. When controlled, all are enormously useful in medicine, but all are subject to major abuse and often lead to addiction.


Kava (Piper methysticum, family Piperaceae) roots and rhizomes are chewed or grated and prepared in cold water, which, when ingested, produce euphoria. This is the common depressant of the South Pacific region. Larger doses can result in impaired vision, lack of muscle coordination, and hypnosis. The active compounds are pyrones.

Opium Poppy.

The opium poppy (Papaver somniferum, family Papaveraceae) has been long in cultivation and is probably native to western Asia. Unripe fruit capsules are incised after the petals fall and the milky exudate is air dried and molded into a gummy substance known as opium. Opium contains many compounds, but the alkaloids morphine and codeine are its most important depressants. From morphine, the illicit drug heroin is produced. Morphine effectively reduces pain and is a strong hypnotic, whereas codeine is widely used as a sedative to allay coughing. All are addictive with serious withdrawal symptoms.

see also Alkaloids; Cannabis; Coca; Ethnobotany; Medicinal Plants; Opium Poppy; Tobacco.

Walter H. Lewis


Lewis, Walter H., and Memory P. F. Elvin-Lewis. Medical Botany: Plants Affecting Man's Health. New York: John Wiley & Sons, 1977.

Ott, Jonathan. Pharmacotheon: Entheogenic Drugs, Their Plant Sources and History. Kennewick, WA: Natural Products Co., 1993.

Schultes, Richard Evans, and Albert Hofmann. The Botany and Chemistry of Hallucinogens. Springfield, IL: Charles C. Thomas, 1980

About this article

Psychoactive Plants

Updated About content Print Article