Porphyrins are the precursors to heme synthesis. Heme is the oxygen binding prosthetic group in hemoglobin and depletion of heme would affect oxygen delivery to the mitochondria and decrease energy production. Also, heme is a component of the electron transport system of mitochon-dria and a prosthetic group in the P450 enzymes which are fundamental in the detox of the body from many organic toxicants including pesticides and PCBs. Just recently, a report was released implying that lack of heme was the major reason why ß-amyloid plaques build up in the brains of Alz-heimer’s diseased subjects. It seems that heme attaches to ß-amyloid helping it remain soluble and excretable. Without adequate heme one of the major pathological diagnostic hallmarks of Alzheimer’s disease appears. It is well known that mercury rapidly disrupts the normal polymerization of tubulin into microtubulin in brain tissue and aberrant tubulin polymerization is a consistent factor observed in Alzheimer’s diseased brain. Therefore, it is the multiple inhibitions of mercury that can cause various neurological and systemic problems and many of these are secondary to the primary site of mercury binding.