Effusions are common in advanced cancer. Intracavitary instillation of various agents such as bleomycin has achieved control rates varying between 20% and 60%. However, serious side effects have also been observed, and cases of death due, for instance, to bleomycin have been reported. Mitoxantrone has been tested recently in the treatment of effusions, and preliminary results suggest high efficacy of this drug in the treatment of peritoneal, pericardial, and pleural effusions. Nevertheless, certain results have been conflicting. In the present study, 29 patients with pleural effusions were treated either with intracavitary bleomycin or intracavitary mitoxantrone. Effusions were controlled almost equally by both agents; 67% with mitoxantrone and 64% with bleomycin. We conclude that both agents can be used successfully in the treatment of pleural effusions.