Commercial deerhorns were extracted in boiling water, the deerhorn extracts were per os introduced into rabbits, and then the effects of the extracts on the antibody productions aginst Escherichia coli antigens were investigated for 4 weeks. The experimental rabbits were divided into 4 groups ; control, only deerhorn, only antigen, and antigen plus deerhorn treated groups. The effects of the treatments were measured by counting the number of blood cells, weighing, and immunoelectrophoresis. The rabbits' body weights gained up to 185% in the deerhorn group, and the other groups gained nearly 120%. The numbers of red blood cells in the antigen plus deerhorn group increased somewhat. However, the numbers of leucocytes gradually increased after one week in the antigen group, and at 4 weeks increased up to 290%. In the antigen plus deerhorn group the numbers of leucocytes increased suddenly up to 189% at one week, but after one week the numbers recovered to normal state. Strangely in the deerhorn group the numbers decreased up to 40%. The amounts of serum globulin increased in the control after one week, but maintained about 130%. In the deerhorn group the amounts increased like the control, but after 4 weeks increased up to 175%. In the antigen group the amounts were not changed until 2 weeks, but after 3 weeks abruptly increased over 175%. In the deerhorn plus antigen group the amounts increased gradually up to 262% until 3 weeks, after 3 and 4 weeks the amounts did not increase. The amounts of serum .gamma.-globulin decreased in the control group, and in the deerhorn group and antigen group the amounts did not change until 2 weeks, but after 3 weeks abruptly increased over 175%. In the deerhorn plus antigen group the amounts increased gradually up to 262% until 3 weeks, after 3 and 4 weeks the amounts did not increase. The amounts of serum ${\gamma}-globulin$ decreased in the control group, and in the deerhorn group and antigen group the amounts did not change until 3 weeks, but after 4 week the amounts slightly increased up to 110%. However, the amounts in the deerhorn plus antigen group did not change until 2 weeks, but after 2 weeks abruptly increased up to 174%. The recognized immunoglobulins were IgG and IgM, and the enhanced immunoglobulin was IgG.