A young lady with a long history of recurrent infections was referred to the gastroenterology department by an infectious disease consultant because of a long history of profuse diarrhoea. A nitroblue tetrazolium (NBT) test performed in her mid-teens had shown zero reduction of the dye. The clinical, biochemical, radiological and endoscopic findings were suggestive of possible underlying Crohn's disease. However, the NBT test was more suggestive of a granulomatous colitis which frequently mimics Crohn's disease in patients with Chronic granulomatous disease. Management with immunosuppressants is proving to be very difficult in this patient in view of recurrent sepsis on introducing these drugs.