colocynth

from The Collaborative International Dictionary of English v.0.48

Colocynth \Col"ocynth\, n. [L. colocynthis, Gr. ?. Cf.
   {Coloquintida}.] (Med.)
   The light spongy pulp of the fruit of the bitter cucumber
   ({Citrullus colocynthis}, or {Cucumis colocynthis}), an
   Asiatic plant allied to the watermelon; coloquintida. It
   comes in white balls, is intensely bitter, and a powerful
   cathartic. Called also {bitter apple}, {bitter cucumber},
   {bitter gourd}.
   [1913 Webster]