Overview:Hallucinogenic plants may be the oldest drugs in the world, and were probably used in rituals during prehistoric times. In the 20th century, LSD and ecstasy became the hallucinogens of choice. This program recounts how science has gradually become aware of the properties of hallucinogens, both natural and synthetic. It also provides a detailed look at the effects of such substances on the brain. Peyote, mushrooms, ayahuasca vine, iboga and yohimbe bark, belladonna flower, and even animal-produced chemicals like bufotenin—secreted from toad skin—are explored in detail.