|Background: We investigated whether chrysin affected MUC5AC mucin production and gene expression induced by phorbol ester (phorbol 12-myristate 13-acetate, PMA) or epidermal growth factor (EGF) from human airway epithelial cells. Methods: Confluent NCI-H292 cells were pretreated with varying concentrations of chrysin for 30 minutes, and were then stimulated with PMA and EGF for 24 hours, respectively. MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay. Results: Concentrations of 10μM and 100μM chrysin were found to inhibit the production of MUC5AC mucin protein induced by PMA; A concentration of 100μM chrysin also inhibited the production of MUC5AC mucin protein induced by EGF; 100μM chrysin inhibited the expression of MUC5AC mucin gene induced by PMA or EGF. The cytotoxicity of chrysin was checked by lactate dehydrogenase assay, and there was no cytotoxic effect observed for chrysin. Conclusion: These results suggest that chrysin can inhibit mucin gene expression and the production of mucin protein by directly acting on airway epithelial cells.