Hydrotherapy cure or water therapy, is the use of water (hot, cold, steam or ice) to relieve discomfort and promote physical well-being.

Hydrotherapy cure can relieve painful or inflamed muscles and joints; rehabilitates injured limbs; reduces fever; relieves headaches; promotes relaxation; treats burns and frostbite; relieves pain associated with childbirth and eliminates skin problems. The temperature of the water used affects the therapeutic properties of the treatment. Hot water is chosen for its relaxing properties and also because it stimulates the immune system.

Warm water can also be used to reduce stress and can be especially relaxing in hot weather.

Cold water is chosen to reduce inflammation. Alternating hot and cold water can stimulate the circulatory system and improve the immune system.

Adding herbs and essential oils to water can enhance its therapeutic value. Steam is frequently used as a carrier for inhaled essential oils to treat respiratory problems.

Since the late 90s, hydrotherapy has been used in intensive care units to treat various serious disorders, including nervous system disorders such as Guillain-Barré syndrome.