The purpose of this study was to evaluate the effects of single large intraperitoneal doses of polydimethylsiloxane fluid. CFN strain rats were administered 0, 51, or 62 ml of the test substance per animal injected intraperitoneally. Smaller doses were given to other groups of rats, however, these rats did not undergo pathological evaluation. Approximately 1 year after administration, the animals in the 51 and 62 ml dose group were sacrificed and gross necropsy and histopathology were performed. Evaluations revealed invasion of the parenchymal organs in the peritoneal cavity by the test substance. Foci of crypting in the liver with demarcated cavities was reported. The pancreas was almost completely replaced by a fatty substance, however, these reactions were not accompanied by any significant foreign body reactions. Based on these observations, the pathological findings are volume related tissue degradation associated with the intraperitoneal injection of large doses of polydimethylsiloxane.