Bronchioloalveolar carcinoma (BAC), a form of pulmonary adeno-carcinoma, presents unique clinical features, such as endobron-chial spread and bronchorrhea in advanced stages. The prognosis for BAC patients in advanced stages is poor, as is the case for patients with other non-small-cell lung cancer (NSCLC) types, because of low susceptibility to conventional chemotherapy. Recently, an orally active, selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (EGFR-TKI), ZD1839 (“Iressa”), has been investigated in phase II clinical studies (IDEAL 1 and IDEAL 2) as monotherapy against chemotherapy-refractory NSCLC, and provided clinically significant antitumor activity. In this study, we examined the therapeutic efficiency of ZD1839 in chemotherapy-refractory BAC patients with bronchorrhea. Two female BAC patients with bronchorrhea were treated once daily with ZD1839 (250 mg/day). In both cases, serous sputum production was dramatically reduced within 3 days of starting the treatment, and hypoxia and radiographic signs of bilateral lung consolidation were visibly improved within 7 days. Following more than 8 months of treatment, no evidence of recurrence or severe adverse events has been observed. These results suggest that this selective EGFR-TKI, ZD1839, may be a powerful agent for treatment of chemotherapy-refractory BAC patients with bronchorrhea. (Cancer Sci 2003; 94: 453–458)