Olmesartan, an angiotensin-receptor blocker frequently prescribed for hypertension, has been commercially available since 2002. In 2012, olmesartan-associated enteropathy was described, and the Food and Drug Administration now requires a black-box warning for olmesartan regarding severe diarrhea. The disorder can be life-threatening and often requires hospitalization. We present three cases that represent different aspects of this disorder, as well as some unusual features.