Abstract: Sixteen patients with malignant peritoneal and/cr pleural effusions were treated with intrac-cavitary injection of Lentinan (LNT made in china). In total，eleven of sixteen patients achieved elnical responses，total remission rate was 69 0 0 In which，five patients was complete remission (31%)，and six was partial remission (38%)，Especially malignant pleural effusions sauced by lung cancer demonstrated the obriously better results, remission rate was 83. 3 0 0 Cfive of six pa-bents). During the therapy, serious toxicities of LNT was not observed The results indicat that LNT is a good drug for treatment of malignant peritoneal or pleural effusions.