I've been wanting to touch on this for a while. I know that a few members here in this group do have some anecdotes about usage of magnets. I will state that it is definitely not what it's cracked up to be and is a result of the placebo effect, although I don't deny their experience...just the facts.
Magnet therapy is the use of static magnets for aid in blood circulation. Claims include helping with pain, healing properties, asthma reduction and more.
One of the best known "magnetizers" was Franz Mesmer. He became all the rage in Paris circa 1778. He would sit patients near a vat of "magnetized" water and would then wave magnetized iron rods around the person. Eventually he discovered, with his colourful attire, that he was just as effective simply leaving the magnets behind and waving his hands around them. I assume this is where "mesmerized" came from.
Interesting to note that, eventually the king appointed a royal inquiry into this with some of the top Parisian physicians and also a U.S. representative by the name of Benjamin Franklin, who believed that the patients did benefit from this practice simply because it kept them away from bloodletting and leeching (similar to the rise in homeopathy at the time...it was a better choice then other practices of the time including the use of mercury to cure).
Magnet Therapy proponents claim that the blood is helped to circulate. Often by watching their videos, they show reddening of the skin around the magnets. This is simply false. The iron in blood is not attracted to the magnet at all. This is because the iron in haemoglobin is not ferromagnetic, but in fact, diamagnetic (it's actually weakly repelled).
The magnets used are often similar to that of fridge magnets. Fridge magnets are designed so that the magnetic field drops off very quickly with a minimal distance. How many papers can you put between your fridge and magnet before the field is so weak it won't hold anything up? Go ahead try it. Similar type magnets were put into foot inserts (yes from that famous company in 1997). Next time you are at a place that sells them, take the package to the greeting card section. See how many cards it'll hold up. Now consider this: If the field is that small, how will it even penetrate your sock, and then your skin?
An MRI (Medical Resonance Imaging) using an ultra strong magnetic field. Know what the most common activity in the body it is used for? Studying blood flow. If magnets had any major effects on blood circulation, an MRI would most certainly cause a person to explode.
Recently (1990's) we've seen a rise in the popularity of magnet therapy thanks due in part to celebrity endorsements from golfers and quarterbacks. "Oh sure," we say, "quarterbacks know pain" so we should take their word for it that a certain product works. Anecdotes are not proof though and often exist due to confusion of correlation and causation. **(see Scambusting wall links for more info).
It seems that any study that is supportive (marginally) was small (under 100 people) and unrepeatable thus suggesting some flaw like the Bayler College of Medicine study. All larger studies since that 1997 one have shown no causation.
http://www.youtube.com/watch?v=8wcKRJvlD1Y (watch this vid to see them prove it)
Demon Haunted World--Carl Sagan
Voodoo Science--Robert Park