Hypersecretion of mucus in the lungs is inhibited by the administration of an epidermal growth factor receptor (EGF-R) antagonist. The EGF-R antagonist may be in the form of a small organic molecule, an antibody, or portion of an antibody that binds to and blocks the EGF receptor. The EGF-R antagonist is preferably administered by injection in an amount sufficient to inhibit formation of goblet cells in pulmonary airways. The degranulation of goblet cells that results in airway mucus production is thereby inhibited. Assays for screening candidate agents that inhibit goblet cell proliferation are also provided.