INTRODUCTION: Diverticulosis occurs when weak spots in the outer layer of colonic muscle weaken giving way to an inner layer of protruding pouches. The progression to diverticulitis occurs when these protruding pouches become inflamed and infected which may ultimately progress to systemic symptoms that include fever, pain, malaise, constipation and vomiting. It is estimated that 50% of the population develops diverticulosis by age 50 and 65% by age 80. Additionally, an estimated 15-20% of the population with diverticulosis will go on to develop diverticulitis. Mild cases of diverticulitis are treated with oral antibiotics and a liquid diet whereas severe cases are treated with IV antibiotics and bowel rest. Here, we present a case of a diverticulitis episode that developed while a patient was already being treated with antibiotics. CASE DESCRIPTION/METHODS: A 64 year old female with a history of endometrial cancer who presented to the hospital for one day history of abdominal pain associated with loose bowel movements. She stated she has had loose bowel movements since starting H. pylori antibiotics that included amoxicillin and clarithromycin 2 weeks prior to presentation. She had an esophagoduodenoscopy 3 months prior that revealed chronic gastritis without dysplasia as well as biopsy proven H. pylori. Her colonoscopy at the same time showed internal hemorrhoids and a single hyperplastic polyp. Her vital signs were unremarkable and she was afebrile. Her white blood cell count on presentation was 13.9. She had a CT scan of the abdomen and pelvis that revealed acute sigmoid diverticulitis and cholelithiasis without evidence of acute cholecystitis. She was subsequently admitted to the hospital and treated with rocephin and flagyl as well as bowel rest. Blood cultures, stool cultures and clostridium difficile cultures were negative. Patient recovered over the next couple of days with resolution of her symptoms and her WBC count. DISCUSSION: This purpose of this case is to highlight the current management and treatment options for diverticulitis. Current guidelines recommend antibiotics and bowel rest during acute episodes of diverticulitis. However, this case represents an unusual scenario where a patient develops acute diverticulitis despite concurrent treatment with antibiotics for ongoing H. pylori infection. Further randomized-controlled trials may help delineate treatment modalities for acute diverticulitis as current treatment guidelines may result in breakthrough diverticulitis episodes.