At any rate, the hallucinogenic experience should not last longer than 8 hours. The most likely situation that would lead to an excessively long trip is the overconsumption of magic mushrooms. There is a tendency, especially for new users, to decide within 30 minutes of ingesting that the mushrooms are unusually weak or that not enough were taken. Taking too many magic mushrooms will not ever be fatal, but it may take the individual a full day to be free of the effects.