Hydrogen peroxide contrast hepatosonography (HPCH), a new technique, was developed for liver examination. On examination, 5-10 ml of 2-3% hydrogen peroxide was injected into the rectum through a dual-channel rubber tube. When hydrogen peroxide passed through the mucosa into the portal vein, the fast flowing contrast echoes were seen, and the liver parenchyma was covered by enhanced echoes. A total of 297 subjects were examined by HPCH with a successful contrast rate of 95.6%. In normal subjects, dense contrast echoes were visible throughout the liver. But in patients with hepatoma, hemangioma, cyst and abscess, contrast echo defects were noted. We conclude that HPCE is of great value in the differentiation of space-occupying lesions and measurement of portal circulation time and blood flow velocity in spite of its untoward reactions.