I am not sure how effective it is. But if you believe it is more than placebo, here are some warnings about it"Doctors who work with magnet therapy have also noticed a difference in the polarities' effects. In his practice as a neurologist, Dr. Philpott, one of Magnet Therapy's authors, has noticed that positive magnetic energy stimulates neurons. He states, "The higher the gauss strength of the positive pole, the higher the level of stimulation. In fact, a sufficiently high positive magnetic field can even evoke seizures and precipitate psychosis in those so predisposed." Robert O. Becker, MD, also observed differences in the polarities' effects. He found that, at first, bodily injuries or tumors have positive electromagnetic energy; then the body draws negative healing energy to the site. In some cases, the body cannot generate and maintain enough negative magnetic energy to heal the injury; hence the reason for using an external magnet to supply a negative static magnetic field, i.e., magnet therapy. The authors of Magnet Therapy warn against using magnets containing both polarities when cancer or any type of infection is present because the positive polarity can encourage tumor growth and increase microbe replication. In addition, people with pacemakers should not put magnets on their chest, and pregnant women should avoid putting magnets on their abdomen since the effect on the fetus is unknown."Townsend Letter for Doctors and Patients, Feb-March 2003 p26(2) Magnet Therapy. (Shorts). (Book Review) Jule Klotter. Full Text: COPYRIGHT 2003 The Townsend Letter Group