A number of hallucinogenic substances are classified chemically as tryptamines. Most of these are found in nature but many, if not all, can be produced synthetically. Psilocybin and psilocyn (4-hydroxy-N,N-dimethyltryptamine) are obtained from certain mushrooms indigenous to tropical and subtropical regions of South America, Mexico, and the United States.
As pure chemicals at doses of 10 to 20 mg, these hallucinogens produce muscle relaxation, dilation of pupils, vivid visual and auditory distortions, and emotional disturbances. However, the effects produced by consuming preparations of dried or brewed mushrooms are far less predictable and largely depend on the particular mushrooms used and the age and preservation of the extract. There are many species of "magic" mushrooms that contain varying amounts of these tryptamines, as well as uncertain amounts of other chemicals. As a consequence, the hallucinogenic activity, as well as the extent of toxicity produced by various plant samples, is often unknown. Generally it is sniffed, smoked, or injected. The effective hallucinogenic dose in humans is about 50 to 100 mg and lasts for about 45 to 60 minutes. Because the effects last only about an hour; the experience has been referred to as a "businessman's trip."