A dithiol that is propane-1,2-dithiol in which one of the methyl hydrogens is replaced by a hydroxy group. a chelating agent originally developed during World War II as an experimental antidote against the arsenic-based poison gas Lewisite, it has been used clinically since 1949 for the treatment of poisoning by arsenic, mercury and gold. It can also be used for treatment of poisoning by antimony, bismuth and possibly thallium, and (with sodium calcium edetate) in cases of acute leaad poisoning. Administration is by (painful) intramuscular injection of a suspension of dimercaprol in peanut oil, typically every 4 hours for 2-10 days depending on the toxicity. In the past, dimercaprol was also used for the treatment of Wilson's disease, a severely debilitating genetic disorder in which the body tends to retain copper, with resultant liver and brain injury.