Total flavonoids from Astragalus membranaceus significantly alleviate alveolar inflammation and collagen deposition in the lung tissue of bleomycin (BLM)-induced pulmonary fibrosis (PF) mouse models, while inhibiting the expression of tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) proteins. The gene discussed is TNF; the disease is pulmonary fibrosis.