Novel anthranilic acid derivatives of the general formula: ##STR1## wherein X is a halogen atom, an alkoxyl group having 1-3 carbon atoms, an alkyl group having 1-3 carbon atoms or a nitro group, n is an integer of 1-2, Y is an alkoxyl group having 1-3 carbon atoms, m is an integer of 2-3, Z is --COCH.dbd.CH-- or --CO--, R.sub.1 is a hydrogen atom or an alkyl group having 1-4 carbon atoms, and pharmaceutically acceptable salts thereof, which derivatives and salts possess a strong antiallergic action and are thus useful as therapeutically active agents for diseases caused by allergies, such as asthma, hay fever, urticaria and atopic dermatitis; an antiallergic composition comprising the same; and a method of alleviating diseases caused by allergies using the same.