The fractions of Epimedii Herba were examined for the immunological effects in ICR mice. Mice were divided into 4 groups and administered orally the fractions of Epimedii Herba for 10 days. The results of this study were summarized as following: (1) The fraction 1 (EtOAc layer) administered group as compared with control group significantly decreased spleen weight, Arthus reaction and hemagglutination (HA) titer but significantly increased circulating white blood cells (WBC). (2) The fraction 2 ($H_20$ layer) administered group as compared with control group significantly decreased liver weight, Arthus reaction and HA titer but significantly increased WBC. (3) The fraction 3 (ppt) administered group as compared with control group significantly increased liver weight, thymus weight rate, delayed type hypersensitivity, phagocytic activity and WBC. The results showed that Frs. 1 and 2 administered groups reduced humoral immune response but increased WBC, and that Fr. 3 administered group increased cell-mediated immune response, phagocytic activity and WBC.