Two of the most important factors in determining safe chelation for autism are dosage and frequency. Too much can be extremely dangerous, and too little can be ineffective. DMPS and DMSA need to be taken in fairly high doses to be truly effective, and because of this, side effects are virtually unavoidable.

The two chemical chelators used most often by the medical profession for autistic kids are transdermal DMPS and oral DMSA. DMPS is a sulfa drug, and even though it is applied topically on the skin instead of ingested orally, there is still absorption of sulfur, which feeds the yeast and bad bacteria in the gut.

This means that if the child has "gut issues" or problems with candida yeast, they are often worsened with transdermal DMPS. And being a sulfa drug, allergic reactions are not uncommon.

Side effects for DMSA include diarrhea, nausea, vomiting, appetite loss and rashes. Both DMPS and DMSA can elevate liver enzymes, and liver and kidney function needs to be closely monitored. Some health care practitioners use various natural chelators such as PCA-Rx clathration formulas and Detoxamin suppositories.

While these products have an excellent reputation, drawbacks include cost (usually several hundreds of dollars)and the time involved; as with any other chelators that are taken into the body, all of the toxins need to be processed through the liver and kidneys, which means that it takes time to eliminate the toxins, usually several months to a year or more.

Another potential factor to consider with any of the above chelators is what is called a "detox reaction", which can occur if large amounts of metals are mobilized through the liver and kidneys. Also, most chelators such as DMSA or DMPS do not remove nickel or aluminum well, nor do they remove chemicals such as food additives, preservatives, nicotine, caffeine, radiation toxins, formaldehyde, and so on.

For an excellent commentary on DMPS and other chelating agents, you can visit the website www.dmpsbackfire.com.