Psilocybin and psilocyn are both chemicals obtained from certain mushrooms found in Mexico and Central America. Like peyote, the mushrooms have been used in native rites for centuries. Dried mushrooms contain about 0.2 to 0.4 percent psilocybin and only trace amounts of psilocyn. The hallucinogenic dose of both substances is about 4 to 8 milligrams or about 2 grams of mushrooms with effects lasting for about six hours. Both psilocybin and psilocyn can be produced synthetically.