The effects of selenium-enriched yeast (Sey) on DTH in immunosuppressive mice have been investigated. It was found that Sey (30, 60, 90 mg?kg-l?d-1?6 d, ig) was able to antagonize lowered DTH by cyclophospha-mide (Cy); Meanwhile, the thymus and spleen weights were increased by Sey (30, or 60 mg?kg-1?d-1) in immunosuppressive mice. Sey also potentiated the lowered ConA and LPS-indu-ced proliferation of splenocytes in DTH mice at the doses of 30, 60, or 90 mg ?kg-1 and 60 or 90 mg?kg-1 respectively. These results suggested that Sey could enhance the functions of lymphocytes.