Barium peritonites are known to be a serious complication of barium enema examinations, being accompanied by a high mortality rate. The authors made their study injecting barium and radioactive 133Ba in the peritoneum of 68 rats without causing damages to the colon, in order to verify the toxicity of barium if injected in the peritoneum, and to evaluate the various extraperitoneal locations. Moreover, they compared the alterations caused by this agent with those consequent to a similar agent, such as talcum. The results show that barium is not toxic on its own: it gives in fact origin to granulomas similar to those caused by talcum; a particular tropism for the lymphatic tissues is present as well.