A two year-old spayed, female German Shepherd Dog was referred to the Cornell University Companion Animal Hospital on October 22, 1998 for further evaluation of diarrhea that was poorly responsive to treatment. The owners first noticed signs of diarrhea and weight loss when the dog was less than a year old, after being boarded at a kennel. The referring veterinarian diagnosed her with exocrine pancreatic insufficiency (EPI) and possible bacterial overgrowth after a physical exam and lab work in March, 1997. Physical exam revealed no abnormalities except a thin dog with diarrhea. The lab work revealed a low trypsin-like immunoreactivity (TLI) of 0.5 ngfml (Reference range: 535 ng/ml) consistent with EPI. The referring veterinarian began treating her for EPI with the following drugs: Tagamet, Viokase powder, and linmodium and Pepto Bismol as needed. She was also cycled on and off Metronidazole and Tetracycline depending on the severity of her clinical signs. She was started on Hills L?D canned with Eukanuba Low Residue dry dog food. Although she has responded to the therapy, the dog was referred to Cornell because of recurrent diarrhea flare-ups and incomplete weight gain.