1400-50;late Middle English (< Middle French) < Latinantidotum < Greekantídoton something given against (i.e., for counteracting), equivalent to anti-anti- + dotón neuter of dotós given, verbid of didónai to give; akin to datum
1510s, from L. antidotum, from Gk. antidoton "given as a remedy," lit. "given against," verbal adj. of antididonai "give in return," from anti- "against" + didonai "to give" (see date (1)). Related: Antidotal (1640s).