Magnets have been used for many centuries for a variety of health purposes. Various products with magnets in them are marketed as health aids, including shoe insoles, bracelets and other jewelry, mattress pads, bandages, headbands and belts. These products are often placed in contact with painful areas of the body with the goal of providing relief.
By various accounts, magnets were discovered when people first noticed the presence of naturally magnetized stones, also called lodestones. By the third century A.D., Greek physicians were using magnetic rings for arthritis and magnetized pills made of amber to stop bleeding. The use of magnets to treat medical problems remained popular well into the 20th century. Today, magnets are used for many different types of pain, including foot pain and back pain from conditions such as arthritis and fibromyalgia.
(SOURCE: NCCAM, National Institutes of Health)