AMYL nitrite was introduced into medical practice as a coronary vasodilator more than a century ago; for much of that time, it was a mainstay, along with nitroglycerin, for angina pectoris. At present it is not used much, having been displaced by the organic nitrates. However, amyl nitrite along with its six-carbon analog, isobutyl nitrite, has come on a renewed popularity—as a drug of abuse. These are the volatile nitrites. The news media have amply reported on their abuse, but articles have appeared in the scientific literature only infrequently. 1 Pharmacology Amyl nitrite is a yellowish, volatile, flammable liquid with a fruity odor. It is unstable and decomposes in the presence of air and light. The severe chest pain of coronary insufficiency can be relieved within 30 seconds by amyl nitrite, and its effects will last for five minutes or more. Amyl nitrite relieves coronary spasm by relaxing smooth muscle fibers