Dimercaprol, also called British anti-Lewisite (BAL), is a medication used to treat acute poisoning by arsenic, mercury, gold, and lead.

[3] Common side effects include high blood pressure, pain at the site of the injection, vomiting, and fever.

[8] Dimercaprol also shows effectiveness against snakebite by potently antagonizing the activity of Zn2+-dependent snake venom metalloproteinases in vitro.

[citation needed] Dimercaprol is itself toxic, with a narrow therapeutic range and a tendency to concentrate arsenic in some organs.

Dimercaprol has been found to form stable chelates in vivo with many other metals including inorganic mercury, antimony, bismuth, cadmium, chromium, cobalt, gold, and nickel.