The peritoneal reaction to starch and its modification by prednisone.

A saline suspension of 1.5 g of starch powder (Biosorb) inoculated into the peritoneal cavity of rats produced a massive granulomatous reaction which persisted for up to 18 months. From 15 months onwards, starch particles could only be detected with PAS staining. Prednisone at a dosage of approximately 1 mg/kg daily by the oral route produced significant reduction of this phenomenon only when commenced 2 weeks before inoculation. Therapy commenced at the time of starch inoculation had only a minor effect on this response, but if commenced 2 weeks after inoculation failed to ameliorate the granulomatous reaction.