The chemical compound amyl nitrite (here referring to isoamyl nitrite) is an alkyl nitrite. It has a characteristic penetrating odour, and produces marked effects on the human body when its vapour is inhaled. It acts as a vasodilator (expanding blood vessels and thus lowering blood pressure) and finds applications in medicine in the treatment of heart disease such as angina. Amyl nitrite is also used to treat cyanide poisoning. It induces the formation of methemoglobin which binds cyanide into non-toxic cyanomethemoglobin. When used recreationally, doses of it are often called poppers. See the article Nitrite inhalants for more information on its recreational use as an inhalant. The effects of amyl nitrite are thought to be due to the action of nitric oxide in the body.
Nitramyl is another name for isoamyl nitrite. The name "amyl nitrite" is actually ambiguous as it can refer not only to 3-methyl-1-nitrosooxybutane, but also its isomers 2-methyl-1-nitrosooxybutane, 3-nitrosooxypentane, 2-nitrosooxypentane, and most commonly 1-nitrosooxypentane-n-amyl nitrite. Other synonyms for amyl nitrite, which may refer to any isomer, include Pentyl Alcohol Nitrite and Nitrous acid, pentyl ester. The name "amyl nitrate" is commonly mistaken for amyl nitrite; they are two different chemicals.