Pseudomyxoma peritonei is a rare condition that develops following rupture of a mucocele of the appendix or the ovary. Twelve cases have been reviewed. Early diagnosis and aggressive surgery offer the best chance for survival of the patient. Recurrent intestinal obstruction is a part of the natural course of the disease, and should be treated surgically by lysis of adhesions and removal of peritoneal implants when they arise. Radiation and systemic chemotherapy do not affect the natural course of the disease or the prognosis.