a concretion found in the stomach or intestines of some animals, esp. ruminants, and sometimes humans, formerly thought to be an antidote for poisons
See bezoar in American Heritage Dictionary 4
(bēˈzôrˌ, -zōrˌ)
noun
A hard indigestible mass of material, such as hair, vegetable fibers, or fruits, found in the stomachs or intestines of animals, especially ruminants, and humans. It was formerly considered to be an antidote to poisons and to possess magic properties.