Hydrotherapy is the branch of Nature cure which treats with the application of water in any form from the solid and fluid to vapour, from ice to steam, internally and externally.

Water is the most flexible medium for producing the thermic and mechanical effects desired and can be applied to a limited area or to the whole surface of the body. No other substance is capable of absorbing so much heat as water does, for which reason it is taken as the standard of specific heat. It also gives out heat with great readiness. It can therefore be used either for abstracting heat from the body or communicating heat to it.

Baths, douches, irrigations-enema, compresses, fomentations, and packs are some of the methods where water can be used. The majority of acute and chronic ailments can be treated as the nerve centres, the heart and blood vessels, the voluntary and involuntary muscles, the digestive system, every organ, every tissue and every cell, also every function throughout the body is effected by proper hydriatic application.