Source : Webster's Revised Unabridged Dictionary (1913)

Gastrointestinal \Gas`tro*in*tes"ti*nal\, a. [Gastro- +
   -intestinal.] (Anat. & Med.)
   Of or pertaining to the stomach and intestines;
   gastroenteric.

Source : WordNet®

gastrointestinal
     adj : of or relating to the stomach and intestines; "a
           gastrointestinal disorder" [syn: {gi}]