Source : Webster's Revised Unabridged Dictionary (1913)

Cathartic \Ca*thar"tic\, Catharical \Ca*thar"ic*al\, a. [Gr. ?,
   fr. ? to cleanse, fr. ? pure; akin to F. chaste.]
   1. (Med.) Cleansing the bowels; promoting evacuations by
      stool; purgative.

   2. Of or pertaining to the purgative principle of senna, as
      cathartic acid.