Abstract: OBJECTIVE To explore the role of Th1/Th2 immune balance in the signal transduction of H1R, PAR-2/TRPV1 itch signal pathway and the intervention mechanism of Fuxian lotion. METHODS There were 60 BALB/c mice randomly divided into 6 groups after 3 days of adaptive feeding, with 10 mice in each group, which were blank control group, model control group, high, medium and low dose group of Fuxian lotion(36, 12, 4 mg·cm^-2) and positive drug control group(1 mg·cm^-2). Except for the blank control group, all other groups were sensitized with 7% and 0.5% 2,4-dinitrochlorobenzene acetone olive oil solution for multiple times. The abdomen and ears of mice in the blank group were coated with acetone solution for control. The drug was administered 24 hours after challenge, twice a day for 10 consecutive days. The ear thickness and the degree of mice ear swelling were measured and scored. The times of scratching the ears of mice were counted. The spleen index was calculated. HE staining was used to observe the pathological changes in mice ear tissue. The serum TNF-α, IL-1β, IL-31 levels were detected by ELISA, the mRNA level of the above immune factors was detected by realtime PCR, and the expression of H1R, PAR-2 and TRPV1 was detected by immunohistochemistry. RESULTS Compared with the blank control group, the ear thickness, ear allergic reaction score, scratching index, the spleen index of mice in the model control group was significantly increased(P<0.01), the TNF-α, IL-1β, IL-31 protein level and mRNA level were significantly increased(P<0.01), and the contents of H1R, PAR-2 and TRPV1 were significantly increased(P<0.01). There were obvious eczema like pathological changes in chronic dermatitis. Compared with the model control group, Fuxian lotion could effectively reduce the degree of auricle swelling, the score of ear allergic reaction, scratch index and spleen index, significantly reduce the levels of TNF-α, IL-1β, IL-31 protein level and mRNA level(P<0.01). The content of H1R in the high dose group of Fuxian lotion, the medium dose group of Fuxian lotion and the positive drug control group was significantly reduced(P<0.01), and the content of PAR-2 and TRPV1 in all dose groups of Fuxian lotion and the positive drug control group were significantly reduced(P<0.01). CONCLUSION Fuxian lotion can improve chronic dermatitis and eczema by regulating the Th1/Th2 immune balance, down regulating the characteristic immune factor TNF-α, IL-1β, IL-31 and interfering with the itch signal pathway H1R, PAR-2/TRPV1 transmission, so as to anti-itching and inhibit inflammatory response.