Airway hypersecretion is a serious and presently untreatable symptom of chronic inflammatory airway diseases. Recently, it has been discovered that epithelial growth factor receptor expression and activation causes mucin production in airways. An epithelial growth factor receptor pathway is implicated in mucus cell differentiation induced by various stimuli; therefore, inhibition of the epithelial growth factor receptor transduction cascade may provide effective new treatments for hypersecretory airway diseases.