Objective: To study Chinese herbal prescription for treatment of eczema on the basis of the suppressive effect of Chinese herbal medicine with type Ⅳ allergic reaction. Methods: Various formulae composed of Chinese herbal medicines possessing suppressive effect on murine allergic contact dermatitis were formed following the therapeutic principles of traditional Chinese medicine in treating eczema, and their effect on ear swelling, ear flake weight, dermal inflammatory infiltration cell count and plasma level of calcitonin gene related peptide ( CGRP) were examined in mice with dinitrofluorobenzene induced dermatitis. The prescription, Composite Poria Decoction was formulated and made into granule form, which was used to treat 63 cases of eczema (atopic dermatitis was excluded), and compared with 59 cases treated with antihistaminic that was aimed at the type I allergic reaction. Results: Experimental study showed that all the 4 Chinese prescriptions had the effect of anti-type Ⅳ allergic reaction, among them, the formula for cooling blood and removing Heat, Wind and Dampness evil possessed the most potent effect in suppressing murine dermatitis, and it was also able to up-regulate the plasma CGRP concentration. The clinical cure rate of Composite Poria Granule treatment was 47.6%, and that of the control was 22.0%. The difference was significant between the two groups (u=2.9555, P<0.01). Conclusions: Chinese herbal medicine has the effect of anti-type Ⅳ allergic reaction. Composite Poria Granule has good effect in treating eczema.