antidote

noun

1. A remedy to counteract the effects of poison.

   “She reached the hospital in time to receive the antidote for the snake venom.”

   “Can'ſt thou not Miniſter to a minde diſeas'd, / Plucke from the Memory a rooted Sorrow, / Raze out the written troubles of the Braine, / And with ſome ſweet Obliuious Antidote / Cleanſe the ſtufft boſome, of that perillous ſtuffe / Which weighes vpon the heart?”

   “The druids […] believed that mistletoe could make barren animals fecund, and that it was an antidote to all poisons.”

2. (figuratively)Something that counteracts or prevents something harmful.

   “We need an antidote for this misinformation.”

verb

1. (transitive)To counteract as an antidote.

   “Had she been less brilliantly efficient it might have ruined her business; had she been less impossibly absurd it would have spoiled her pleasure, but the two things simply antidoted one another.”

   “For his part, the patient must avoid some commonplace substances in order to avoid antidoting or stopping the action of the homeopathic remedy[…]”