Definition and characteristics

The term "balneotherapy" is generally applied to everything relating to spa treatment, including the drinking of waters and the use of hot baths and natural vapor baths, as well as of the various kinds of mud and sand used for hot applications. Balneotherapy refers to the medical use of these spas, as opposed to recreational use. Common minerals found in spa waters are sodium, magnesium, calcium and iron, as well as arsenic, lithium, potassium, manganese, bromine, and iodine. All these may be contained in the peat that is commonly used in preparation of spa waters. Resorts may also add minerals or essential oils to naturally-occurring hot springs. Though balneotherapy commonly refers to mineral baths, the term may also apply to water treatments using regular hot or cold tap water.

Mud-baths are also included in balneotherapy, and the dirt and water used to mix mud baths may also contain minerals which are thought to have beneficial properties.