Introduction: The fibrinolytic system has a major role as a defense mechanism against thrombus formation. Net fibrinolytic activity in plasma reflects the balance between tissue-type plasminogen activator and plasminogen activator inhibitor (PAI). PAI is the main factor determining overall fibrinolytic activity. Materials and methods: We examined the effects of oral administration of vitamin E, an antioxidant, on fibrinolytic activity and oxidative stress in patients with coronary spastic angina. Forty patients with coronary spastic angina were randomly assigned into two treatment groups, either vitamin E group (alpha-tocopherot acetate, 400 mg/day) or placebo group by means of computerized system. PAI activity and thioredoxin, a marker of oxidative stress, levels were measured before and at the end of 1 month treatment. Results: Before treatment, the levels of PAI activity and thioredoxin were increased in patients with coronary spastic angina as compared with control subjects (n = 17) (PAI activity levels: 13.6 +/- 1.4 vs. 7.6 +/- 2.2 IU/ml, p < 0.05, thioredoxin levels: 22.8 +/- 1.7 vs. 16.0 +/- 1.4 ng/ml, p < 0.05). In patients with coronary spastic angina, administration of vitamin E decreased both PAI activity and thioredoxin levels (PAI activity levels: 14.7 +/- 1.7 to 7.5 +/- 1.6 IU/ml, p < 0.01, thioredoxin levels: 23.3 +/- 2.4 to 15.1 +/- 2.5 ng/ml, p < 0.01), whereas placebo had no effect on these variables. Conclusions: Oral administration of vitamin E improved fibrinolytic activity and the improvement was associated with a decrease in oxidative stress. Administration of vitamin E is possible to be an effective adjunct therapy of coronary spasm in the absence of coronary atherosclerosis. (C) 2004 Elsevier Ltd. All rights reserved.