You may be thinking of DMSO: http://en.wikipedia.org/wiki/Dimethyl_sulfoxide http://en.wikipedia.org/wiki/Dimethyl_sulfoxide It's a gel that easily penetrates

You may be thinking of DMSO: http://en.wikipedia.org/wiki/Dimethyl_sulfoxide http://en.wikipedia.org/wiki/Dimethyl_sulfoxide It's a gel that easily penetrates the skin and can serve as a drug delivery system. The KGB was said to use it to administer poison to assassination victims. Its history has been plagued by controversy, which has slowed down research on its many potential medical uses.