From the current study, the medicinal bath fumigation is the role of temperature, mechanical force and drug efficacy of the three, in order to promote blood circulation, accelerate metabolism, regulate the meridians and viscera, eliminate siltation and pain, relax the tendons, bone and tendons, warm tendons and dispel cold, remove wind and dampness to regulate joint dysfunction, as well as disease prevention and fitness. The therapeutic effect of medicinal baths is multifaceted, first of all, it is directly related to the role of water itself. When the drug is dissolved in water, it forms the so-called medicinal solution, which has the following characteristics compared with oral and other drug delivery methods: direct absorption: the skin has the role of absorbing the chemical substances in contact with it, water-soluble, lipid-soluble and other solvents dissolved in the drug can be absorbed by the skin, but of course, the water-soluble is still more important. Although the drugs absorbed through the skin are not as direct and rapid as oral and intravenous administration and can be given in large quantities, they have the advantages of being continuous, gentle, with few side effects and not causing gastrointestinal reactions. Therefore, it is especially suitable for chronic diseases. In addition, for certain diseases of the skin and surgery, the drug penetrates directly into the local area or acts directly with the causative factors, which has the advantages that cannot be replaced by other routes of drug delivery. Enhancement of drug effect: The properties of water can be used to enhance the original drug effect. Such as vasodilator drugs, the use of warming method, so that the physical effect and pharmacological effects of the combination. Certain bacteria, toxic infections, the drug solution on the one hand, continuous drug delivery, on the one hand, to remove the local pathogenic and metabolic production of special products, to be better than the simple local topical drug efficacy. A cause of drugs using wine (alcohol) soluble, the reason is the same. Vapor inhalation: The vapor produced when the water temperature is high, can be part of the drug components through the vapor absorption by the mouth and nose or act on other parts of the mucous membrane and skin, in addition to pharmacological effects, but also wetting effect. Therefore, it is especially suitable for respiratory system, five senses and skin diseases. The overall mechanism of action: The overall action of the medicinal bath refers to the use of drugs through the skin, orifices, acupuncture points and other parts of the direct absorption, into the meridians and blood channels, the transmission of the whole body and play its pharmacological effect. In recent years, people’s research on the mechanism of external treatment of traditional Chinese medicine baths has been intensifying, and it is believed that in addition to the direct entry of drugs into the blood circulation to exert their own pharmacological effects, there is also the role of adjusting the functions of various systems, tissues and organs and the immune function of the body. The local action mechanism: The local action of medicinal bath refers to the local therapeutic and health care effect of Chinese medicine on the lesion. The effect of Chinese medicine bath on local tissues can make the concentration of drugs in local tissues significantly higher than that in other parts, so the local curative effect is obvious and quick.