Acute haemoperitoneum in patients with coagulation disorders or those under anticoagulation therapy is a diagnostic and therapeutic dilemma. Since radiological imaging is often insufficient for establishing the origin of the bleeding, a laparoscopic approach can be considered before a laparotomy is performed in haemodynamically unstable patients. A 32-year-old woman receiving coumadin therapy presented with acute lower abdominal complaints. Due to suspicion of a tubo-ovarian abscess after the initial ultrasound, a conservative treatment was administered. A routine blood count after 12 hours showed a significant reduction in haemoglobin. During the CT scan, the patient developed unstable haemodynamics. Based on deteriorating coagulation parameters, mass transfusion and stabilization of the coagulation were performed but were not successful. Therefore an interventional laparoscopy was performed and a ruptured ovarian cyst was found to be the cause of bleeding. A ruptured ovarian cyst might be the cause of an acute abdomen and haemoperitoneum in young women. Therefore cyclus anamnesis and the exclusion of other obvious reasons for acute mass bleeding, i.e. ectopic pregnancy, can justify the laparoscopic approach after stabilization of the coagulation parameters. Long-term combined oral contraceptive therapy is indispensable for the prevention of these sorts of bleeding complications.