Provided is a composition for prevention or treatment of an allergic disease, the composition including an inotodiol compound and a chaga mushroom (Inonotus obliquus) extract including an inotodiol compound as an active ingredient. More particularly, it was found that when an inotodiol compound or a chaga mushroom extract containing an inotodiol compound as one of the active ingredients is administered to a mouse model in which a food allergy was induced, symptoms induced by the allergy were alleviated and cured. Thus, the inotodiol compound or the chaga mushroom extract containing an inotodiol compound as an active ingredient is expected to be useful as a composition for prevention or treatment of an allergic disease.