The effects of Chelidonii Herba on the cell mediate and humoral immune responses were investigated in ICR mice. ICR mice received intraperitoneal injection of methanol extracts (ether fraction, buthanol fraction, water fraction) for 5 days before sensitization. The change of body weight (%), the organ weight ratio (%), the numbers of RBC and WBC, the ear swelling by dinitrofluorobenzene, the titers of hemagglutination (HA) and hemolysin (HY) to SRBC were determined. The results were as follows; 1. The change of body weight (%) showed a tendency of increasing generally. 2. The weight of spleen (%) revealed decreasing but that of thymus revealed increasing. 3. Ear swelling was maxium at 48 hours after challenge and was significantly decreased in the groups treated with Ether, Buthanol and Water. 4. The numbers of RBC and WBC were decreased generally. 5. HA and HY titers were decreased significantly.