Man has used hallucinogenic plants and mushrooms for centuries. The characteristics of these plants that led to their incorporation into important ritualistic and spiritual traditions, however, have also resulted in their widespread propagation and abuse. Hallucinogenic plants have long been depicted as innocuous substances, yet their unpredictable nature makes intoxication potentially dangerous. In present-day society, there is greater access to these drugs and a growing trend among the younger generations to experiment with these plants in a recreational fashion. Emergency physicians need to be aware of the potential sources of plant hallucinogens and the spectrum of toxic effects. A review of the more common hallucinogenic plants and fungi is discussed with reference to historical, pharmacological and clinical aspects of these intoxications.