Abstract: Objectives To study the effect of mustard seeds on dermal and systemic typeⅠhypersensitivity and its mechanism. Methods Balb/c mice were randomly divided into control group,mustard seed group and normal group.Mice in control group and normal group had normal forage and those in mustard seed group had forage containing 5% mustard seeds.Three weeks later,10 mice were selected from control group and mustard seed group respectively to establish capillary permeability model by intracutaneous injection of histamine and compound 48/80,and 6 mice were selected from mustard seed group and control group to establish typeⅠhypersensitivity model by intracutaneous injection of ovalbumin（OVA） to observe the effect of mustard seeds on typeⅠhypersensitivity. Results Mustard seeds could inhibit capillary permeability（P＜0.05） but not serum IgE,IL-4 and IFN-γlevels（P＞0.05） in mice. Conclusion Mustard seeds can inhibit dermal typeⅠhypersensitivity.