Abstract:The anti-tumor effect of Cetraria laevigata polysaceharides has been investigated in mice using sarcoma 180; Ehrlich ascitie tumor, cervical carcinoma u-14 and leukemia L7217. The results show that Cstraria laevigata polysaccharides may inhibit the growth of sarcoma 180,Ehrlich ascitic tumor and cervical carcinoma u-14 in mice at a dose of 200mg/kg ip (1/5 LD50).However, the survival time of leukemia L7217 wasn‘t prolonged. The reticuloendothelial system phagocytic function in mice was increased at ip doses of 50mg/kg and 100mg/kg(1/10 and 1/20 LD50).