It is found that vitamin K3 and vitamin K5 that are often used in pharmaceuticals and foods or ACNQ and DHNA that can proliferate a useful bacterium bifidobacterium can prevent the degranulation of a basophil-like cell strain, have a potent degranulation-preventing effect and are useful as anti-allergic agents or foods. Disclosed is an anti-allergic agent comprising, as active ingredient(s), one or more substances selected from the group consisting of 2-amino-3-carboxy-1,4-naphthoquinone, 1,4-dihydroxy-2-naphthoic acid, 1,4-naphthoquinone, 4-amino-2-methyl-1-naphthol, 2-methyl-1,4-naphthoquinone and 2-amino-3-chloro-1,4-naphthoquinone and salts thereof.
