Ginkgo Biloba A 20 or 40 mg/kg ip mice inhibited passive cutaneous allergic response and the same dose given to ratsip ip inhibited mast cell degranulation. It antagonized the contractile effect of the isolated guinea pig ileum smooth muscles induced by the antigen, HA or SRS-A and kept the pulmonary flow volume. It inhibited the swolling of the ear induced by dinitrochlorbenzene in mice.