Naturally occurring Inflammatory Bowel Disease (IBD) animal models are hard to come by. HZ-Bio is screening its colony of >30,000 cynomolgus monkeys for animal with diarrhea. After ruling out obvious bacterial and parasitic infection and confirming the extent and frequency of diarrhea, animals are subjected to examination by colonoscopy with biopsy of pathological lesions. Additional stool and serum biomarkers will be assessed upon positive confirmation from colonoscopy.