I read in Hal Huggins' book , "It's all in your Head" that everyone has differnt immune systems and genetics. Mercury will be the "last straw" and tip the scales . It also makes inherited illnesses come on faster than they normally would.

Even though some people dont experience symptoms yet-- they quite possible will as the years progress and they age. Their immune system will be lower and the mercury in their bodies will "tip the scale" and BAM!-- illness will strike for no reason.

It also depends on the amount of mercury fillings and how much mercury. Even one Mercury filling is enough to cause subtle symptoms. Better out than in!!