We conducted this study to investigate whether berberine signifi cantly affects MUC5AC mucin gene expression and mucin production induced by epidermal growth factor (EGF), phorbol 12-myristate 13-acetate (PMA) or tumor necrosis factor-${alpha}$ (TNF-${alpha}$) from human airway epithelial cells. Confl uent NCI-H292 cells were pretreated with varying concentrations of berberine for 30 min and then stimulated with EGF, PMA or TNF-${alpha}$ for 24 h. MUC5AC mucin gene expression and mucin production were measured by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Berberine was found to inhibit the expression of MUC5AC mucin gene induced by EGF, PMA or TNF-${alpha}$. Berberine also inhibited the production of MUC5AC mucin protein stimulated by the same inducers. This result suggests that berberine can regulate the expression of mucin gene and production of mucin protein, by directly acting on human airway epithelial cells.