ObjectiveTo isolate an endophytic fungus, which can produce podophyllotoxin, from an endangered medical plant Sinopodophyllum hexandrum, and to investigate the inhibitory effect of its fermentation broth against S180 sarcoma. MethodsEndophytic fungal strains were isolated and purified by microbiological tissue isolating methods from the fresh roots and stems of Sinopodophyllum hexandrum. The fermentation broths of the isolates were investigated by HPLC, so as to screen for podophyllotoxinproducing strains. The antitumor effects of endophytic fungus fermentation broths were evaluated in a mouse model bearing S180 sarcoma. The orbital blood samples were obtained for leukocyte and lymphocyte count. ResultsStrain T8, identified as Cephalosporium sp. was podophyllotoxinproducing. The tumor weight of T8 group was lower than that of the model group (P<0.05) and higher than that of the cyclophosphamide group (P<0.05). The inhibitory rate of fermentation broth of T8 group was significantly lower than that of cyclophosphamide group (P<0.05). Compared with the model group, the fermentation broth of T8 group significantly promoted the proliferation of leukocytes and lymphocytes. ConclusionThe fermentation broth of fungus T8 can inhibit tumor growth and may serve as an adjuvant drug for tumor therapy after attenuation.