Relation of body mass index and waist-to-height ratio to cardiovascular disease risk factors in children and adolescents: the Bogalusa Heart Study. Freedman DS, Kahn HS, Mei Z, Grummer-Strawn LM, Dietz WH, Srinivasan SR, Berenson GS. [PubMed-indexed for MEDLINE].
Smelling salts release ammonia (NH3) gas, which triggers an inhalation reflex (that is, causes the muscles that control breathing to work faster) by irritating the mucous membranes of the nose and lungs. Although these hypothetical mechanisms have been discussed, it is likely that smelling salts are not effective.
Smelling salts, or salt of hartshorn, were originally made from the ammonia of male deer horns. Today, smelling salts are made from ammonium carbonate and perfume. Smelling salts should be kept tightly bottled when not in use due to the noxious odor.