Although it has reported that Dietary Genbakugenmai-su(G-Ac) has an enhancing effect on immunogloblin (Ig) productivity in rats, its effect was not elucidated whether the individual properties of G-Ac or not. In this study, we compared the dietary effect of between G-Ac and acetic acid as general dietary vinegar. As result, serum Ig concentration was dose-dependently increased by both of G-Ac and acetic acid, and the effect of academic acid was almost equal or higher than the effect of G-Ac. Ig productivity of MLN lymphocytes was also reinforced by both of G-Ac and acetic acid. And its effect of acetic acid was greater than that of G-Ac. On the other hand, Ig productivity of spleen lymphocytes was not effected by G-Ac or acetic acid. These ersults suggested that acetic acid feeding reinforces Ig productivity by MLN lymphcytes, and its effect contributed to the increment of Ig concentration in serum.