Hydrotherapy Hydrotherapy is the use of a variety of different components, temperature, pressure of water, in different forms of action on the body to achieve mechanical and chemical stimulation to prevent and treat disease. Introduction The effect of water on the body is extremely complex, the body’s response changes in many ways, so far, can only be considered a non-specific systemic stimulation therapy, is through the neurohumoral pathway in the body to produce the results of the extremely complex biophysical changes, its role is mainly through the following channels: 1, phytoncotic action; 2, adrenocortical hormone action; 3, sulfhydryl action; 4, histamine; 5, protein metabolism; 6, ion metabolism Histamine action; 5, protein metabolism; 6, ion metabolism; 7, normalization action. Classification: according to temperature Ice bath: 0 ℃ ~ 4 ℃; cold water bath: 5 ℃ ~ 25 ℃; low temperature water bath: 26 ℃ ~ 32 ℃; do not feel warm water bath: 33 ℃ ~ 35 ℃; warm water bath: 36 ℃ ~ 38 ℃; hot water bath: 39 ℃ ~ 42 ℃; high heat water bath: > 43 ℃. According to the composition of the water division sea water bath, fresh water bath, hot spring bath, drug bath (Western medicine bath and Chinese medicine bath), mineral bath, gas bath. Classification by water form Ice bath (winter swimming), water bath, air bath. Classification by therapeutic effect There are efficacy therapies such as sedative, excitatory, antipyretic, sweating, strong stimulation, gentle stimulation, and exercise.