Clostridium difficile (CD)-associated diarrhoea and colitis may relapse in up to 20% of treated patients. We present a patient who failed to respond over a 6-month period to treatment either singly or in combination with metronidazole, vancomycin, rifampicin, cholestyramine and probiotics. Her diarrhoea rapidly resolved after a 3-day course of intravenous immunoglobulin. This treatment may compensate for a failed immune response to CD toxin and should be considered for relapsing CD-associated diarrhoea where there is no response to conventional treatment strategies.