BER-5 is a potent MrgX2 antagonist. BER-5 possess broad-spectrum antagonistic activity against a diverse range of MrgX2 agonists. BER-5 can inhibit Substance P (SP) (HY-P0201)-induced degranulation of LAD2 cells. BER-5 attenuates SP-induced allergic reactions in mice. BER-5 can be used for the study of allergic reactions[1].