Fourteen patients with brain metastases from previously untreated small-cell lung cancer (SCLC) were treated with three courses of systemic chemotherapy as an initial mode of treatment. Whole brain irradiation was given concurrently with the fourth course of chemotherapy. The chemotherapy consisted of cyclophosphamide, 600 mg/m2 intravenously (IV) on day 1; doxorubicin, 50 mg/m2 IV on day 1; vincristine, 1.5 mg IV days 1 and 5; and etoposide, 60 mg/m2 IV days 3 through 5; all repeated every 3 weeks with dosage adjustments. There were ten men and four women, with a median age of 59 years (range, 47 to 75). Six patients had multiple brain lesions, and the brain was the sole site of distant metastasis in four patients. Three patients were inevaluable for response in the brain, as two died early and the third dropped out of the trial too soon. Brain lesions responded to chemotherapy in nine (one complete remission [CR], eight partial remissions [PR]) of 11 (82%) evaluable patients, and objective responses in the extracranial lesions were documented in nine (one CR, eight PR) of 12 (75%) evaluable patients. Median survival was 34 weeks (range, 1 to 93), and two patients are still alive. Toxicity was significant, with severe granulocytopenia (less than 500/microL) and thrombocytopenia (less than 50,000/microL) observed in 85% and 15% of patients, respectively. Six patients had major infectious complications, which resulted in septic deaths in two. However, there was no deterioration of neurologic status during the initial phase of treatment with chemotherapy. We conclude that systemic chemotherapy alone can induce objective regression of metastatic brain lesions in patients with previously untreated SCLC.