late 15c., ultimately from Arabic bazahr, from Persian pad-zahr "counter-poison," from pad "protecting, guardian, master" (from Iranian *patar-, cf. Avestan patar-, from PIE *pa-tor-, from root *pa- "to protect, feed") + zahr "poison" (from Old Iranian *jathra, from PIE *gwhn-tro-, from root *gwhen- "to strike, kill;" see bane). Originally "antidote," later specifically in reference to a concoction from solid matter found in the stomachs and intestines of ruminants, which was held to have antidotal qualities (1570s).
bezoar be·zoar (bē'zôr')
A hard indigestible mass of material, such as hair, vegetable fibers, or the seeds and skins of fruits, formed in the alimentary canal.