An elderly woman with longstanding insulin dependent diabetes tried to commit suicide by injecting 400 units of insulin subcutaneously (usual total daily dose 56 units). She was admitted to hospital within the hour and treated with the aid of an artificial pancreas. This avoided the usual difficulty of the physician having to cope with rapid and substantial fluctuations in blood glucose concentrations and 67 hours after the overdose insulin was reinstituted. Using an artificial pancreas in insulin overdose is an important advance in management and may avoid the need for surgical intervention such as excising the site of injection.