How Do Smelling Salts Work?

When a woman's heart raced and she started to faint, it was common to reach for the smelling salts — and the arms of a strapping gentleman. (Photo: Everett Collection /Shutterstock).

When you think of smelling salts, you may think of swooning 19th century Victorian women. For many years, smelling salts had a straightforward use — to revive someone who had just fainted or fallen unconscious. But recently, smelling salts have gotten a reputation for having a slightly less innocent purpose.

How Do Smelling Salts Work?

Smelling salts, or ammonia capsules as they are also called, are usually chemical compounds of ammonium carbonate. They are sometimes mixed with fragrance. When ammonia is released into the air, and subsequently sniffed by someone, it irritates the mucous lining of the nose. This, in turn, triggers an inhalation reflex that causes a person to breathe faster. It can also raise a person’s blood pressure and heart rate, and increase brain activity by activating a person’s sympathetic nervous system, which shuts down when a person faints.

Smelling Salts in Sports

Nowadays, smelling salts have gained notoriety for being used in competitive sports. In boxing matches in the 1950s, it was common for a boxer to inhale smelling salts if he was on the verge of unconsciousness after a blow to the head. It would revive the boxer enough to get back in the ring and finish the match.

Smelling salts were later banned from the sport because it was reasoned that in any situation where a person has just suffered a head injury, he should be heading to the hospital instead of back into the ring. Smelling salts would essentially make a bad situation worse by giving a boxer an artificial burst of energy just as he was teetering on the edge of consciousness.

More recently, smelling salts have been used by players in the NFL to help them get through a game. In 2005, Mike Freeman wrote an article for the Florida Times-Union that exposed how widespread the use of smelling salts were, describing the field next to the locker room and players bench as being littered with used ammonia capsules.

Indeed, in a piece just published by The New York Times, Eric Kester describes his experience as an NFL ball boy, in which he would constantly provide smelling salts to injured and weary players. “After almost every crowd-pleasing hit, a player would stagger off the field, steady himself the best he could, sometimes vomit a little, and tilt his head to the sky. Then, with eyes squeezed shut in pain, he’d scream “Eric!” and I’d dash over and say, “It’s O.K., I’m right here, got just what you need,” he writes.

How Safe Are They?

Smelling salts by themselves are probably not dangerous, concludes Dr. Paul McCrory in a 2006 article in the British Journal of Sports Medicine. Rather, “With regard to sporting concussions, the real danger is that reaching for smelling salts in this situation is not a substitute for a careful and complete neurological assessment,” he states. “More serious head injuries may often masquerade in the early stages as a minor head injury and inexperienced [caregivers] may falsely assume that an initial improvement, thought to be due to the beneficial effects of smelling salts, may well mask the development of more sinister complications.”