Clostridium difficile (C. difficile) pseudomembraneous colitis was diagnosed in a 13-year-old boy with Hodgkin's disease 3 months after autologous bone marrow transplantation. Hematopoiesis was fully reconstituted at the time. C. difficile infection occurred after gall bladder empyema had been treated conservatively with i.v. antibiotics and prophylactic 4-week administration of oral amoxicillin. C. difficile colitis was diagnosed early and intensive supportive therapy combined with administration of i.v. and subsequently oral vancomycin therapy failed. It is a phenomenon rarely seen and successful eradication of the clostridium infection was only achieved by a combination of higher dose vancomycin with metronidazole. During the post-colitis recovery the patient experienced a relapse of Hodgkin's disease and died following further surgical intervention 137 days post-transplantation.