Objective:To study the effects of supranutrional levels of yeast-selenium on antioxida-tion status and immune function in mice with tumour.Method:Sixty KM mice were divided into three groups: control group,yeast-selenium Ⅰ group and Ⅱgroup.The mice were supplemented with 0.5ml normal saline,3.2 ?g and 6.4 ?g yeast-selenium respectively by gavage on time a day based on the low selenium diet.The mice were inoculated with Ehrich ascites carcinoma(EAC) after 13 d.The tumour weight and immune function and antioxidative indices in blood were measured after 23 d.Results: The two yeast-selenium levels increased the activities of GSHPx(P