Some frogs and toads secrete substances from glands in their skin that can have hallucinogenic effects when ingested or dried and smoked. The best known such species is Bufo alvarins, the Colorado River toad.
Using hallucinogens derived from frogs or toads is risky. According to the Burke Museum, these substances are neurotoxins which interfere directly with the nervous system and can impair thinking, movement or cardiac function. Users also risk "bad trips," which are highly unpleasant hallucinatory experiences that can be very frightening. The National Institute on Drug Abuse states that the effects of hallucinogens are highly unreliable and can vary between users or even between different uses by the same user.