A small number of users suffer psychotic episodes which last for weeks. Certain parts of an original drug experience may recur without subsequent drug ingestion. Such flashbacks are usually brief, but can last hours. Psilocybin Psilocybin is the active ingredient in a number of psychedelic mushrooms. Native American shamans used such mushrooms in rituals and to treat illnesses.
Mushrooms vary greatly in strength.
One strong plant might contain as much psilocybin as ten weaker ones. Effects last about five or six hours after ingestion. Nausea and dizziness accompany a bitter taste with the use of psilocybin. Aside from the possibility of a bad trip, people who harvest mushrooms face the danger of accidentally ingesting poisonous toadstools. Some species, such as the Amanita Phalloides, can cause permanent liver damage or death.