AIM: To study the antioxidant effects of extract solution of bamboo leaves in mice and the effects of scavenging hydroxyl free radical ( ·OH- ) in vitro. METHODS: The mice were treated with extract solution of bamboo leaves (8,12 g·kg -1 ,ig) daily for 30 d. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in blood and the contents of lipofuscin (LF),malondialdehyde (MDA) and SOD in liver,and brain and heart by biochemical methods were determined. ·OH- was induced by ascorbate-Cu 2+ reaction system,and the effect of extract solution of bamboo leaves on scavenging ·OH- was estimated by colorimetry. RESULTS: The extract solution of bamboo leaves could significantly increase the activities of SOD and GSH-Px in blood and the activities of SOD in liver,brain and heart in mice,and obviously reduce the contents of LF and MDA in mice tissues. The extract solution of bamboo leaves of 0.05 - 1.0 g·L -1 had markedly effects on scavenging ·OH- from 7.8 % to 87.7 % in dose-effect relationship (r= 0.976 ). CONCULSION: The extract solution of bamboo leaves can obviously inhibit damage of free radical and prevent lipid peroxidation. The mechanisms may associate with directly scavenging ·OH- ,and with increasing the activities of antioxidation enzymes in mice tissues.