S-Allylmercaptocysteine (25 and 50 mg/kg; oral gavage) could significantly ameliorate the pathological structure, and decrease inflammatory cell infiltration and pro-inflammatory cytokines in bronchoalveolar lavage fluid (BALF) in BLM-induced pulmonary fibrosis mice. S-Allylmercaptocysteine shows an anti-fibrosis effect by increasing anti-oxidants like HO-1, GSH and SOD as well as decreasing hydroxyproline (HYP) in BLM-induced mice.