Water has many properties that are poorly understood by science. It is the only natural compound that is lighter when it is solid than as a liquid . Water is also considered a universal solvent, which means that it will eventually break down any compound immersed within it.

Hydrotherapy is the use of water to promote healing. It may be used as a liquid or steam, taken internally or externally either by immersion or by inhalation, and taken hot or cold. The water may have a high level of salts or be extremely pure, depending upon the reason for its use.

The healing benefits of water have been known for thousands of years and are well documented in ancient literature, Roman baths being most famous. These were built at the sites of natural springs, often where the water was hot or miner-ally rich. The popularity of the spa was at its height in Europe during the 18th and 19th centuries, and hundreds of towns became famous for their waters. Water is now a popular therapy in health farms and hospitals throughout Europe, and the increasing number of whirlpools, hot tubs and Jacuzzis in hotels and sports clubs is testimony to the immediate beneficial effects of immersion in water.

Therapies include wrapping, baths, douches or showers, sitz baths and steam or Turkish baths. Herb and mineral baths and sea-water baths are also used. Sprays and steam may be used externally and inhalations with or without essential oils may be of benefit . Hot water is used to stimulate and then relax, while cold water invigorates. Alternate use of hot and cold water stimulates blood and lymph circulation, tones tissues and relieves congestion. Sitz baths are used in this way to treat pelvic and abdominal disorders, liver and kidney problems, constipation and piles. Hydrotherapy is also beneficial for people with physical disabilities since the buoyancy of the water allows an increased range of movement.

Hydrotherapy is one of the safest and cheapest ways of relieving common ailments, and is therefore ideal for self-help treatment. Exercising in water brings relief from aches and pains, increased relaxation and greater flexibility, and also promotes fitness and a sense of well-being.