Psilocybin is a chemical obtained from certain types of fresh or dried mushrooms. Street names include Magic Mushrooms, Mushrooms, and Shrooms. Mushrooms containing psilocybin are available fresh or dried and have long, slender stems topped by caps with dark gills on the underside. Fresh mushrooms have white or whitish-gray stems; the caps are dark brown around the edges and light brown or white in the center. Dried mushrooms are usually rusty brown with isolated areas of off-white.

Psilocybin mushrooms are ingested orally. They may also be brewed as a tea or added to other foods to mask their bitter flavor. The psychological consequences of psilocybin use include hallucinations and an inability to discern fantasy from reality. Panic reactions and psychosis also may occur, particularly if a user ingests a large dose.

The physical effects include nausea, vomiting, muscle weakness, and lack of coordination. Psilocybin’s effects are similar to other hallucinogens, such as mescaline and peyote. Effects of overdose include longer, more intense “trip” episodes, psychosis, and possible death. Abuse of psilocybin mushrooms could also lead to poisoning if one of the many varieties of poisonous mushrooms is incorrectly identified as a psilocybin mushroom.

Psilocybin is a Schedule I substance under the Controlled Substances Act, meaning that it has a high potential for abuse, no currently accepted medical use in treatment in the United States, and a lack of accepted safety for use under medical supervision. Psilocybin mushrooms are found in Mexico, Central America, and the United States.