Abstract: Objective To study the therapeutical effect of glutathione（GL）,a powerful antioxidant on the symptoms and ECG in patients with coronary heart disease and its mechanisms.Methods Eighty-five subjects with coronary heart disease were recruited（45 male and 40 female）.The patients were randomized to receive GL （240 mg,ivgtt,qd,for 14 days,n=44）on the top of conventional treatment（aspirin+β-blocks+ACEI）or conven- tional treatement alone（control,n=41）.The serum MDA,SOD,NO levels were determined.Electrocardio- graphy（ST stage,T wave）was examined.Results GL significantly improved clinical symptoms scores（2.0+0.5 vs control:1.5+0.5,P＜0.01）,as well as electrocardiogram（ST）scores（GL:1.8+3.8 vs before:10.1+5.9; control:4.2+3.7 vs before:9.8+5.9,respectively,P＜0.01）with markedly intergroups differences（1.8+3.8 vs control:4.2+3.7 P＜0.01）. The improvement of clinical symptoms and ECG were coincident with pro- nouncedly decreases in MDA（GL:4.4±0.7 vs before:5.1±0.8 mmol/L;control:4.7+0.7 vs before:5.2+0.3 mol/L,P＜0.01 or 0.05）,increases in SOD（GL:82.3±12.5 vs before:68.7±15.6 mmol/L;control:73.5+ 15.9 vs before:68.3+15.0 mmol/L,P＜0.01 or 0.05）,as well as meaningful increased in NO（GL:56.7±12.5 vs before:52.2±16.6;control:53.2+15.7 vs before:50.5+12.6 mmol/L,P all＜0.01）.After GL treatment, all the MDA,SOD,NO levels were better than that in control group.Conculsion Glutathione significantly im- prove the clinical symptoms and ECG scores of patients with coronary héart disease,which was associated with de- creases in free radical oxidation and improve endothelial function.