<prompt> BAL British anti-Lewisite, Dimercaprol is of no value for the treatment of poisoning byArsenicMercuryZincSelenium  <response>: BAL British anti-Lewisite, Dimercaprol is a dithiol-chelating agent used in the treatment of poisoning by the heavy metals.It is of no value for the treatment of poisoning by selenium, iron, or cadmium; in fact, it is contraindicated in these poisonings because the BAL metal mercaptide complex may be more toxic than the metal alone. 