The mercury found in Merthiolate and Mercurochrome is toxic to both people and the environment. MedlinePlus says that mercury-containing Merthiolate can cause poisoning if applied to the body in small amounts for a long period of time. Mercurochrome was originally allowed for sale over-the-counter because it pre-dated the FDA, says Cecil Adams.Continue Reading
MedlinePlus says that Merthiolate in over-the-counter products was banned by the Food and Drug Agency (FDA) in the late 1990s. Cecil Adams on The Straight Dope says that Mercurochrome was banned from being sold over-the-counter in 1998 by the FDA.
Due to some reports of mercury poisoning related to the use of Mercurochrome, the FDA re-classified it as a drug in 1998, meaning that someone has to prove it is safe for use before it can be sold again. As of 2014, no one has tried to do so.Learn more about Vitamins & Supplements