Question:When I was a kid growing up, the antiseptics of choice for cuts and scrapes were iodine and Mercurochrome that left nice brown and red stains. We still have iodine, but where has all the Mercurochrome gone?

ANSWER:In case you don't know, Mercurochrome is a mercury-containing compound used as an antibacterial antiseptic. My mom kept an abundant supply of Mercurochrome around and a scraped knee or small finger cut got a little sting and turned red with its application. There was even a yellow-green sheen to it. But no more. Mercurochrome (technically known as merbromin) is off the drug store shelves. Has it been banned? Well, sort of.

The Food and Drug Administration has the responsibility of determining whether or not pharmaceuticals and food additives are safe. With a 1938 act of Congress, there were hundreds of unchecked products. Products like Mercurochrome that had been around for years with seemingly no ill effects were given a "generally recognized as safe" status. In 1978, the FDA began a review of mercury-containing, over-the-counter products. In general, FDA approval requires studies to be done to show a product is safe. This had never been done with Mercurochrome.

Even though Mercurochrome had just a small amount of mercury, mercury poisoning was a consideration. (You may recall the recent FDA advisory that warned pregnant women and young children not to eat certain fish because of high mercury levels.) To affect testing, the FDA pulled the GRAS status and classified mercurochrome as a "new drug" in 1998, which meant that anyone wanting to sell it nationwide had to put it through the rigorous and costly approval process. No one did, and the FDA forbade the sale of Mercurochrome across state lines, which effectively killed the product.

Mercurochrome will probably never be tested because there are more effective antiseptics, such as Merthiolate and metaphen. Whether or not you agree, it was one of those better-safe-than-sorry decisions. Mercury poisoning can harm various body organs and fetuses.

In some states, mercury fever thermometers are illegal. The electronic digital type is safer. Then there's the controversy about amalgam tooth filling, which is about 50 percent mercury. There are claims that the mercury filters out of the fillings into the body. The FDA has not seen fit to ban amalgam from dentistry. (Plastic fillings are now commonly used.) As I've written several times, the Mad Hatter in Lewis Carroll's "Alice in Wonderland" is said to have suffered from mercury poisoning. A mercury compound was used to treat beaver skins for hats in the 1800s, and it was common for workers in the hatting industry to acquire mercury poisoning, which affected the brain and made one a bit weird.

I've got a mouthful of amalgam fillings, so I have a mercurial excuse for my actions.

C.P.S. (Curious Postscript):Veni, Vidi, VISA. I came, I saw, I did a little shopping. - Anon.

Curious about something? Send your questions to Dr. Jerry D. Wilson, College of Science and Mathematics, Lander University, Greenwood, SC 29649, or e-mail jerry@curiosity-corner.net. Selected questions will appear in the Curiosity Corner. For Curiosity Corner background, go to www.curiosity-corner.net.