METHODS A 54-year-old patient presented with acute abdominal pain that had started after having a bowel movement. METHODS Ultrasound examination revealed free intraabdominal fluid with no signs of organ rupture. CT-scan showed a peripherally located ruptured aneurysm of a branch of the superior mesenteric artery. METHODS Intraoperatively the aneurysm was then ligated. A vascular reconstruction or bowel resection was not necessary. After an uneventful postoperative course, the patient could be discharged from the hospital on postoperative day four. Two weeks later the patient was readmitted, with fever and dyspnea. Transesophageal echocardiogram suggested the presence of bacterial growth on the aortic and mitral valves. Blood cultures and valvular vegetations grew Streptococcus viridans. The diagnosed infective endocarditis was caused by a tooth-infection, that had been recurrent for one year. After treatment of the tooth infection, the mitral and aortic valves were replaced without any complications. CONCLUSIONS Because of the high mortality associated with rupture, it is important that visceral aneurysms are taken into consideration in the differential diagnosis of unexplained abdominal pain. It should also be kept in mind that the aneurysm could be due to an infective endocarditis. Therefore, echography should be carried out in each case, to avoid further complications and to give optimal treatment.