Hospitals have been offering massage for many years. It's been proven effective in the treatments of pain (chronic, post-surgery and illness-related), arthritis and circulation problems, not to mention muscle soreness.
Massage is part of a group of therapies known as manipulative and body-based medicine. This category also includes practices like chiropractic and yoga (another top five therapy). In manipulative and body-based medicine, the idea is that alignment of joints and the proper circulation to muscle groups and other tissues are crucial to good health. Massage addresses this concept in a direct way, through the working of muscles, tendons and other soft tissues.
A massage therapist uses hands and arms (and sometimes other body parts, like feet) to manipulate the patient's body. Massage increases blood circulation to a part of the body, or throughout the body in general, by rubbing a muscle group and extending joints. This manipulation stimulates the flow of blood to that area, which, in turn, increases the oxygen available to muscles and tissues. Good blood flow is essential for the body to work efficiently and fight disease.
Up next are the related practices of yoga and meditation, which also seek to stimulate areas of the body -- but with the added component of mind-based work.