A case of recurrent small cell carcinoma of the lung, accompanied by intraperitoneal metastasis, was orally treated with etoposide (50 mg/day) for 3 consecutive weeks. Subjective symptoms such as abdominal pain began to improve one week after the start of treatment. After three weeks of treatment, these symptoms disappeared completely, and CT findings also improved. The serum NSE level, which was as high as 89.5 ng/ml before treatment, fell to 8.7 ng/ml after 3 weeks of treatment. The patient is now being followed at the outpatient clinic of our hospital. As adverse reactions to the drug, alopecia and leukopenia were observed. The leukopenia appeared in the third week of treatment, but the white blood cell count returned to normal soon after the drug was discontinued.