[Problem] The present invention addresses the problem of examining the antioxidant effect of a lactobacillus beverage. The present invention also addresses the problem of finding out an active ingredient thereof. [Solution] It was found that a lactobacillus beverage has an antioxidant effect. It was also found that an antioxidant substance as an active ingredient thereof is 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP). The present invention pertains to a lactobacillus beverage containing an antioxidant component. The antioxidant component is DDMP.