Boomers, magic mushrooms, shrooms. The experience is generally viewed as a milder, and shorter LSD-like experience.

Hallucinogenic mushrooms are the second most common form of hallucinogen used in the United States. Use of mushrooms dates back to 100 AD, in Mexico and Central America, where the Aztecs built statues of mushrooms. They considered mushrooms sacred and called them "God's flesh." The active principales are psilocybin and psilocin. They act within 20 to 30 minutes and can last up to four hours.

The first effect is generally a feeling of relaxation. After that, with high doses, users experience some visual distortions, mainly visual.

The physical effects of mushrooms are very mild. At low doses, users experience simple feelings of relaxation and physical heaviness or lightness. At higher doses, lightheadedness, numbness of the tongue, lips, or mouth, shivering or sweating, nausea and anxiety can occur.

It is believed that psilocybin's effect has something to do with the neurotransmitter serotonin. Scientists have found that there are two major groups of serotonin receptors. Mushrooms acts on both classes, by blocking one while it stimulated the other. The serotonin group stimulated, serotonin 2, was found to be responsible for causing hallucinations. However, the research is still inconclusive, since other drugs (such as antidepressants) that increase serotonin levels in the brain, do not seem to cause hallucinations.

Mushrooms can be hard to identify and there are a number of different types of mushrooms that can induce the same type of hallucinations as do psilocybin mushrooms. However, many of them contain psychoactive compounds that can be extremely dangerous or lethal to the user. Some species contain toxins that produce fatal damage to the liver and kidneys.

sources:
Kuhn, Cynthia, Scott Swartzwelder and Wilkie Wilson. Buzzed : the straight facts about the most used and abused drugs from alcohol to ecstasy. New York: W.W. Norton, 1998.

"psilocybin" Britannica.com. Vers. 2001
1999-2001. Encyclopædia Britannica.
1 Sep. 2000
(http://www.britannica.com/eb/article?eu="63265"&tocid="0"&query=psilocybin)