Medical equipment has a nuclear magnet, high magnetic field of 3T or more, are not harmful to the human body. It is recognized that in all radiology medical equipment, nuclear magnets are the safest. That is to say, people are not afraid of magnetic fields, more afraid of rays. It is true that high magnetic fields have some negative effects on the human body, but the limited amount of magnets in magnet bracelets is not likely to have any effect on the human body at all. Some people claim that magnets provide the magnetic force to change physiological organization, and even believe that every cell has positive and negative poles, while others claim that magnets can enhance the circulation of blood. In fact, there is no evidence to prove that there is any interaction between the tissue cells or blood of the human body and the magnetic field. Iron ions in red blood cells, not only have no ferromagnetism, but are even anti-magnetic and will not be attracted by the magnetic field. It is well known that hot compresses will promote blood circulation, and the result is that the skin will turn red. If magnets can really promote the circulation of blood, why is there no reddening of the skin which is in direct contact with the magnets? The effect of magnetic therapy is only the so-called psychological suggestion ability, and does not have very direct and obvious medical effects. Magnet bracelet through the weak magnetic lines of force constantly stimulate the wrist microcirculation system, to promote blood circulation, improve the human physiological magnetic field, eliminate fatigue has a very weak effect, indeed, sleep has some benefits