Disclosed is the use of an immunomodulator compound of Formula A, or a pharmaceutically acceptable salt thereof, in the preparation of a dosage form for treating, preventing, inhibiting or reducing allergic disease or its effects in a subject, wherein, n is 2, R is hydrogen, acyl, or alkyl, and X is L-tryptophan or D-tryptophan. Allergic disease are for example atopic bronchial asthma.