Plasma antioxidative activity was determined by spectrophotometric method by estimation of plasma volume resulting in inhibition of free radical reaction rate by 50%. The study comprised 40 patients with pulmonary tuberculosis (25 men, 15 women) aged 19-77 years (mean 48.5). Every patient had infiltrative pulmonary tuberculosis diagnosed. After 1-month therapy with tuberculostatic drugs vitamins C and E were added in 15 patients in a daily dose of 1.0 g and 600 mg respectively. The control group consisted of 16 clinically healthy subjects (12 men, 4 women) aged 28-57 years (mean 42.5). Decrease in plasma antioxidative activity was found in patients as compared to the controls before as well as after therapy with tuberculostatic drugs. However, in patients with added vitamins (after 1-month tuberculostatic therapy) increase in plasma antioxidant activity was observed.