Resveratrol has a preventive potential on bleomycin-induced pulmonary fibrosis in prophylactic use; however, it was not studied in the treatment of the fibrosis. This study investigated the role of resveratrol on the treatment of bleomycin-induced pulmonary fibrosis. Intratracheal bleomycin (2.5 mg/kg) was given in fibrosis groups and saline in controls. First dose of resveratrol was given 14 days after bleomycin and continued until sacrifice. On 29th day, fibrosis in lung was estimated by Aschoft's criteria and hydroxyproline content. Bleomycine increased the fibrosis score (3.70 +/- 1.04) and hydroxyproline levels (4.99 +/- 0.90 mg/g tissue) as compared to control rats (1.02 +/- 0.61 and 1.88 +/- 0.59 mg/g), respectively. These were reduced to 3.16 +/- 1.58 (P = 0.0001) and 3.08 +/- 0.73 (P > 0.05), respectively, by resveratrol. Tissue malondialdehyde levels in the bleomycin-treated rats were higher (0.55 +/- 0.22 nmol/mg protein) than that of control rats (0.16 +/- 0.07; P = 0.0001) and this was reduced to 0.16 +/- 0.06 by resveratrol (P = 0.0001). Tissue total antioxidant capacity is reduced (0.027 +/- 0.01) by bleomycine administration when compared control rats (0.055 +/- 0.012 mmol Trolox Equiv/mg protein; P = 0.0001) and increased to 0.041 +/- 0.008 (P = 0.001) by resveratrol. We concluded that resveratrol has some promising potential on the treatment of bleomycin-induced pulmonary fibrosis in rats. However, different doses of the drug should be further studied.