Purpose: Hepatopulmonary syndrome is an arterial oxygenation disorder brought about by advanced liver failure and pulmonary vascular dilatations. The reason why hypoxia develops in hepatopulmonary syndrome depends on the broadening of perialveolar capillary veins. Our study aims to investigate the effects of Flavanoid on hepatopulmonary syndrome through its inhibition of nitric oxide. Methods: Three groups, each having 8 rats, were formed within the scope of our study. Group I (the control group) only received laparatomy, group II received choledoch ligation, and g roup III was administered Flavanoid (90% flavonoid diosmin, 10% flavonoid hesperidin) following choledoch ligation. The rats were administered Flavanoid at week two following choledoch ligation. The rats' livers and lungs were examined histopathologically following a five-week follow-up and the perialveolar vein diameters were measured. Arterial blood gases and biochemical parameters were evaluated. Results: It was seen that fibrosis and oxidative damage in the liver wit h obstructive jaundice as well as hypoxia with pulmonary perialveolar vein si zes were significa ntly lower than the other group with cirrhosis formed through the administration of Flavanoid. Conclusion: We have concluded that Flavanoid administration might be useful in the treatment of hypoxia in hepatopulmonary syndrome and the delay of cirrhosis contraction. Copyright © 2013, the Korean Surgical Society.