Evening primrose oil(EPO) is a rich source of cis-linoleic acid and gammalinolenic acid(GLA) and has been used as a therapeutic agent in various skin diseases such as atopic dermatitis.

The purpose of this study was to evaluate the suppressive effect of EPO on murine contact sensitivity.

BALB/c mice were divided into 3 groups, positive control, experimental and negative control groups: the positive control group represents a group of mice which were sensitized and challenged with DNFB, the experimental group represents EPO-pretreated positive control group and the negative control group represents a group of mice which were challenged only. The changes of ear thickness were measured, and H & E staining and immunohistochemical staining for ICAM-1 expression of ear skin were performed to evaluate the histological changes of each group.

The Pretreatment of mice with EPO resulted in suppression of contact sensitivity by more than 82%. On H & E staining, only a mild inflammatory reaction was observed in the dermis. Also ICAM-1 expression of keratinocytes, the intensity of the staining was significantly decreased in the experimental group compared with positive group.

Our study indicates that EPO was able to suppress the induction of contact sensitivity.