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.
Instead it has bile salts (acids) which can 1  : Emulsify fats and break it down into small particles. This is a detergent-like action of bile.  Helps the body absorb the breakdown products of fat in the gut. Bile salts bind with lipids to form micelles.