Hydrotherapy is the use of water to maintain health or promote healing. Ice, steam, and hot, tepid, and cold water are all used in a number of different ways–some widely accepted, others controversial. For example, external treatments, such as the application of ice to a sprained ankle or soaking in a hot tub to soothe sore muscles, have become common remedies and some are universally prescribed by both conventional and alternative practitioners, particularly naturopaths. However, internal therapies such as colonic irrigation are considered suspect and even dangerous by most mainstream doctors.