<;P>;PROBLEM TO BE SOLVED: To provide an immunopotentiating agent given by using natural components to which chemical treatment is not applied, and to provide food and drink furnished with an immunopotentiating effect. <;P>;SOLUTION: The immunopotentiating agent and the immunopotentiating food and drink are each given by combining gramineous grains, such as oats, a processed product thereof, and lactic acid bacteria, such as Lactobacillus gasseri. A mixture of the gramineous grains, the processed product thereof, and the lactic acid bacteria is synegistically increased in a cytokine production quantity and enhanced in the immunopotentiating effect, because a macrophage is more activated by the mixture when compared with a macrophage activated by each of the components. <;P>;COPYRIGHT: (C)2006,JPO&NCIPI