Balneotherapy is a treatment with healing waters, which includes bathing and physiotherapy in thermal water, therapeutic drinks, medical massage, and water jet massage. It is based on the buoyancy, physical properties, temperature, and chemical effects of mineral water. Throughout European and Japanese medical institutions, balneology and hot spring therapy is very much a part of routine medical treatment. The mechanism of balneotherapy is not yet completely understood. Balneotherapeutic procedures are mainly performed for the prevention, treatment, and rehabilitation of musculoskeletal diseases, but they have also proven useful for various other indications such as for the treatment or rehabilitation of dermatological diseases, immuno-inflammatory diseases, chronic pain syndromes, chronic cardiac diseases, and metabolic syndromes or neurological diseases as well as in the rehabilitation of patients with psychiatric conditions. Balneotherapy works well in the case of muscle tension, as it is relieving and relaxing, and it may be associated with improvement of various diseases. However, further investigations are necessary to determine the effectiveness, safety, standard procedures, and potential side effects of balneotherapy.