To confirm efficacy of Pricklyash Peel Decoction on allergic conjunctivitis, and to make a preliminary analysis on its action mechanism.Methods:To observe improvement of vital signs and changes of pathological section by various concentrations of the decoction.Blood serum was taken to determine changes of parameters including IgG1, IgE and IL-4.Results:Pricklyash Peel Decoction has significantly improved the model rats' eye acute symptoms, decreased reaction of late cell and reduced the levels of IgG1, IgE and IL-4 in blood serum.Conclusions:Pricklyash Peel Decoction has active effect on allergic conjunctivitis.Its action mechanism is related to effective decrease of immune globulin and immune factors in blood serum.