From April 1993 to September 1994, a prospective multicenter phase III clinical trial on PVI in the management of malignant effusion was carried out. Five hundred and nine patients, including 382 with lung cancer, 54 with breast cancer, 16 with malignant lymphoma, 57 with other malignancies complicated with pleural effusion were treated with intrapleural injections of PVI. The over-all response rate was 82.7% (421/509). For comparison, 41 patients with cancer of the lung (n = 31), breast (n = 6) and other sites (n = 4) also complicated with pleural effusion were treated by intrapleural PDD. The overall response rate in the latter treatment group was 61.0% (25/41). Fever and local pain were the major adverse reactions in the PVI treated patients while nausea, vomiting and myelosuppression in the PDD-treated control patients.