Experiments were performed on rats to investigate the effect of doses of capsaicin on the immune response. Olive oil and the 0.3 mg, 1.0 mg and 3.0 mg/kg administration of capsaicin in olive oil were injected intraperitoneally every day for 4 weeks. Rats were sensitized and challenged with sheep red blood cells (S-RBC). Immune responses were evaluated by organ weight, HA and HY titer, Arthus reaction, delayed type hypersensitivity (DTH) and Rosette froming cell. Following results have observed. 1) The weight of spleen and thymus were increased by doses of compared with control group, but the body weight of rats was decreased. 2) HA titer, Arthus reaction and DTH were significntly decreased by doses of capsaicin as compared with control group. 3) Rosette forming cell in spleen cells was decreased according to the increase of capsaicin doses. These results suggested that high dose of capsaicin decrease humoral and cellular immune response in rats.