Right-sided infective endocarditis is generally known to occur in drug abusers and in patients with long indwelling venous catheters. Paradoxical cerebral embolization is a rare condition causing cerebrovascular accident. This patient had neither apparent drug history nor predisposing factors to infective endocarditis and systemic thromboembolism. It was a very rare case that was complicated not only by both-sided infective endocarditis but also by paradoxical embolism through a patent foramen ovale (PFO). CaseA 36-year-old female was admitted to our hospital for evaluation of 5 days of high fever of unknown origin and abrupt abnormal behavioral change associated with mental disturbance. Her vital signs were as follows: body temperature, 39.7 ; blood pressure, 120/80 mmHg; pulse, 140 bpm. On physical examination, the patient was drowsy and disoriented. Cardiac auscultation revealed a grade II pan-systolic murmur at the right sternal border. There were no prominent peripheral signs or neurological deficits. The chest Xray showed mild cardiomegaly and pulmonary artery dilation but she had no symptoms of heart failure. An abdominal CT showed a right iliopsoas abscess; a head CT showed a hematoma at the right frontal lobe, and edema of the brain stem and right occipital lobe. Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) disclosed a huge vegetation of the tricuspid valve and an atrial septal aneurysm (ASA) with PFO that had a right to left shunt confirmed by intravenous bubble injection (Figure 1, 2). The mitral and aortic valve was not affected, and during color Doppler examination, no abnormal flow was detected. Additionally, methicillinsensitive Staphylococcus aureus was detected by blood culture. We diagnosed right-sided infective endocarditis complicated by systemic septic embolization and started large doses of two kinds of antibiotic therapy, as well as immediate management of mild right heart