Provided is an enhancer of the expression of a biological defense function factor, which can be achieved as a novel use application of a licorice extract. The enhancer of the expression of a biological defense function factor comprises, as an active ingredient, a licorice extract that is soluble in water and ethanol and does not contain glycyrrhizin or glabridin, has an activity of enhancing the expression of BCL-XL, survivin, P53, SOD and HO-1 that are biological defense function factors, and also has an activity of inhibiting the expression of iNOS. The enhancer can be used as a BCL-XL expression enhancer, a survivin expression enhancer, a P53 expression enhancer, an SOD expression enhancer, an HO-1 expression enhancer, or an inhibitor of the expression of iNOS that has an oxidative stress stimulating activity.
