To optimize the processing method of wine-steamed Vaccariae Semen and preliminarily investigate its mechanism of action in treating seborrheic dermatitis.Methods:A high-performance liquid chromatography(HPLC) method was established to detect flavonoid glycosides and erythraline in Vaccariae Semen.The response surface methodology was used to examine the effects of material-to-liquid ratio，soaking time，and steaming time to optimize the processing method.A rat model of seborrheic dermatitis was established，and the potential mechanism of wine-steamed Vaccariae Semen in the treatment of seborrheic dermatitis was explored by observing hematoxylin-eosin(HE) stained pathological sections and measuring serum levels of interferon-γ(IFN-γ)，interleukin-2(IL-2)，interleukin-4(IL-4)，and interleukin-10(IL-10).Results:Through response surface experiments，the optimal processing conditions for wine-steamed Vaccariae Semen were determined to be a material-to-liquid ratio of 25 kg/100 kg(auxiliary material/herb)，a soaking time of 2.4 h，and a steaming time of 2.4 h.In terms of efficacy，compared to the model group，significant differences in skin lesion scores were observed in both the positive control group and the wine-steamed group(P<0.01).HE staining revealed that wine-steamed Vaccariae Semen could repair and improve necrosis in the epidermal and dermal layers of the seborrheic dermatitis model，as well as reduce lymphocyte infiltration and connective tissue hyperplasia caused by seborrheic dermatitis.However，the positive control group caused epidermal thickening during treatment.Additionally，both the positive control group and the wine-steamed group increased serum levels of IL-2 and IFN-γ，while reducing serum levels of IL-4 and IL-10 in the model rats.Conclusion:The optimal processing method for wine-steamed Vaccariae Semen was determined，and wine-steamed Vaccariae Semen can alleviate seborrheic dermatitis to a certain extent.Its mechanism may be related to regulating the balance between T-helper cell 1(Th1) and T-helper cell 2(Th2).