Magnetic fields stimulate all your vital functions and help your body to regenerate itself. The idea is to stimulate what the body already knows to produce by itself, rathen than "inject it" chemicals. It is therefore simply to rebalance the energy system by exposure to a magnetic field at the pain.
This method is well tolerated by the skin and does not attack the tissues or other organs. Magnetic therapy does not cause allergies and it is possible to use it at any age.
Magnetic therapy is not recommanded in case of presence of a pacemaker, any active device implanted or pregnancy ( > 3 months ). For further details or doubt, follow the requirements of you doctor.