Idiopathic pulmonary fibrosis (IPF) is a chronic, devastating and fatal disease characterized by aberrant fibroblasts proliferation, oxidative stress and collagen accumulation in the interstitial tissue. We aimed to evaluate in the present study the efficacy of Thymus vulagris extract (TVE) on an experimental model of pulmonary fibrosis induced by bleomycin (BLM). Wistar rats were given a single dose of BLM (4 mg/kg, intratracheal), while TVE (50, 100 and 200 mg/kg, intraperitoneal) was administered 3 days later and continued for 4 weeks. We reveled by HPLC analysis an important amount of phenolic bioactive compounds such as rosmarinic and vanillic acids. Our results showed a significant decrease of catalase and superoxide dismutase activities and an increase in lipid peroxidation compared to control group after BLM injection. Treatment with TVE (200 mg/kg) was able to normalize the level of these oxidative markers and to decrease collagen accumulation compared to BLM group. Moreover, this high dose of TVE have no renal or hepatic cytotoxic effects. This study allowed us to conclude that thyme extract has a strong antioxidant and antifibrotic activities due to its high content of polyphenols.