① The cleansing effect of medicinal bath on the skin. After the skin is first soaked and bathed in the medicated bath solution, its exudates, scabs, scales and pollutants are removed, which is conducive to the penetration of herbal liquid into the skin lesions and improves the therapeutic effect. ② Warm physical and chemical effects. Warm bath has a sedative, tranquilizing, anti-itching effect and reduce symptoms, so that the patient is comfortable; hot bath can make the skin capillary expansion, accelerate blood flow, the body’s qi and blood flow, improve local microcirculation, promote metabolism, accelerate tissue repair. ③ The medicinal effect of traditional Chinese medicine. Chinese medicine bath, belongs to the category of traditional Chinese medicine external treatment, such as internal medicine, also adheres to the principle of the motherland medical evidence-based treatment.