Quercetin can reduce the expression of transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA), and tumor necrosis factor-α (TNF-α), inhibit alveolar cell apoptosis and reduce lung tissue inflammation and fibrosis injury in rats, which can effectively improve lung fibrosis (Ma et al., 2018; Zhang et al., 2018; Wei et al., 2019). The gene discussed is TGFB1; the disease is pulmonary fibrosis.