Source : Webster's Revised Unabridged Dictionary (1913)

Antidote \An"ti*dote\, n. [L. antidotum, Gr. ? (sc. ?), fr. ?
   given against; ? against + ? to give: cf. F. antidote. See
   {Dose}, n.]
   1. A remedy to counteract the effects of poison, or of
      anything noxious taken into the stomach; -- used with
      against, for, or to; as, an antidote against, for, or to,
      poison.

   2. Whatever tends to prevent mischievous effects, or to
      counteract evil which something else might produce.

Antidote \An"ti*dote\, v. t.
   1. To counteract or prevent the effects of, by giving or
      taking an antidote.

            Nor could Alexander himself . . . antidote . . . the
            poisonous draught, when it had once got into his
            veins.                                --South.

   2. To fortify or preserve by an antidote.

Source : WordNet®

antidote
     n : a remedy that stops or controls the effects of a poison
         [syn: {counterpoison}]