Focal nodular hyperplasia of the liver may occur with increased frequency in young women who have been taking oral contraceptives. Patients may present with massive intraperitoneal hemorrhage requiring immediate surgical intervention. These nodules may be multiple and occasionally pedunculated, mimicking ovarian cysts. Liver function tests are nondiagnostic. A liver scan and arteriogram are often helpful in determining a diagnosis. Percutaneous liver biopsy is contraindicated. Large nodules should be resected, and continued use of oral contraceptives is contraindicated.