Does the metal in old fillings cause poison in the mouth?

No. If the fillings are left undisturbed, there are no deleterious effects from old fillings. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV vaccine. Wish you good health!

The old fillings if not redone or changed to a composites, if broken or have some leakage would only cause further decay and some discomfort. No poison, but some small evidence of mercury content. Always practice good oral hygiene. A metal filling lasts for years, without any serious harm to mouth as evidenced in the research.

No. If that were true wouldn't your parents and grandparents generation already be sick or dead?