We treated a 68-year-old man with cirrhosis of the liver associated with moderate hypoxemia. Contrast-enhanced echocardiography revealed late opacification of the left ventricle, and pulmonary perfusion imaging with 99mTc macroaggregated albumin showed evidence of a significant uptake in both lungs and in the liver, spleen, and kidneys. Right cardiac catheterization revealed pulmonary hypotension, low pulmonary vascular resistance, and high cardiac output. We administered prostaglandin F2 alpha intravenously (0.2 microgram/kg/min for 30 minutes) and indomethacin orally (75 mg/day for three days). There was some degree of resolution of the hypoxemia and increases in both pulmonary arterial pressure and pulmonary vascular resistance. These findings suggest that the pathophysiology of hepatogenic pulmonary angiodysplasia is a reversible intrapulmonary vascular dilatation. These conditions can to some extent be modulated by vasoactive substances such as prostaglandins or other eicosanoids.