From 11/87 until 7/90 103 patients entered a prospective randomized trial on the treatment of malignant pleural effusions (MPE) with intrapleural mitoxantrone versus placebo (pleural tube alone with instillation of isotonic NaCl). Our data suggest no statistically significant difference between the two arms with respect to response and response duration. There is no influence on survival time. The toxicity is moderate, with only fever occurring more often in the mitoxantrone arm. We recommend performance of pleurodesis in patients with MPE first by sufficient drainage with a tube of 16-20 char. Only in instances of failure it is necessary to add sclerosing agents such as tetracycline, etc.