Smelling salts, also known as ammonia inhalants, spirit of hartshorn or sal volatile, are chemical compounds used as stimulants to restore consciousness after fainting.

Usage

The usual active compound is ammonium carbonate—a colorless-to-white, crystalline solid ((NH₄)₂CO₃). Because most modern solutions are mixed with water, they should properly be called "aromatic spirits of ammonia". Modern solutions may also contain other products to perfume or act in conjunction with the ammonia, such as lavender oil or eucalyptus oil. Historically, smelling salts have been used on people feeling faint, or who have fainted. They are usually administered by others, but may be self-administered. Smelling salts are often used on athletes (particularly boxers) who have been dazed or knocked unconscious to restore consciousness and mental alertness. Smelling salts are now banned in most boxing competitions. They are also used as a form of stimulant in athletic competitions (such as powerlifting,

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and ice hockey) to "wake up" competitors to perform better. In 2005, Michael Strahan estimated that 70–80% of National Football League players were using smelling salts as stimulants.

History

Smelling salts have been used since Roman times and are mentioned in the writings of Pliny as ''Hammoniacus sal''. Evidence exists of use in the 13th century by alchemists as sal ammoniac. In the 14th-century " The Canon's Yeoman's Tale" one of Chaucer's ''

The Canterbury Tales ''The Canterbury Tales'' ( enm, Tales of Caunterbury) is a collection of twenty-four stories that runs to over 17,000 lines written in Middle English by Geoffrey Chaucer between 1387 and 1400. It is widely regarded as Chaucer's ''Masterpiece, ...

'', an alchemist purports to use ''sal armonyak''. In the 17th century, the distillation of an ammonia solution from shavings of harts' (deer) horns and hooves led to the alternative name for smelling salts as spirit or salt of hartshorn. They were widely used in

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Britain to revive fainting women, and in some areas constables would carry a container of them for the purpose. During this time, smelling salts were commonly dissolved with perfume in vinegar or alcohol and soaked onto a sponge, which was then carried on the person in a decorative container called a vinaigrette. The ''sal volatile'' appears several times in Dickens' novel '' Nicholas Nickleby''. The use of smelling salts was widely recommended during the Second World War, with all workplaces advised by the British Red Cross and

St. John Ambulance St John Ambulance is the name of a number of affiliated organisations in different countries which teach and provide first aid and emergency medical services, and are primarily staffed by volunteers. The associations are overseen by the internat ...

to keep smelling salts in their first aid boxes.

Physiological action

Solid ammonium carbonate and ammonium bicarbonate salts partly dissociate to form , and vapour as follows: : : The smelling salts release ammonia () gas, which triggers an

inhalation Inhalation (or Inspiration) happens when air or other gases enter the lungs. Inhalation of air Inhalation of air, as part of the cycle of breathing, is a vital process for all human life. The process is autonomic (though there are exceptions ...

reflex. It causes the muscles that control breathing to work faster by irritating the mucous membranes of the nose and

lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...

s. Fainting can be caused by excessive

parasympathetic The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of t ...

and vagal activity that slows the heart and decreases

perfusion Perfusion is the passage of fluid through the circulatory system or lymphatic system to an organ or a tissue, usually referring to the delivery of blood to a capillary bed in tissue. Perfusion is measured as the rate at which blood is deliver ...

of the brain. The sympathetic irritant effect is exploited to counteract these vagal parasympathetic effects and thereby reverse the faint.

Risks

Ammonia gas is toxic in large concentrations for prolonged periods and can be fatal. If a high concentration of ammonia is inhaled too close to the nostril, it might burn the nasal or oral mucosa. The suggested distance is . The use of ammonia smelling salts to revive people injured during sport is not recommended because it may inhibit or delay a proper and thorough neurological assessment by a healthcare professional, such as after concussions when hospitalization may be advisable, and some governing bodies recommend specifically against it. The irritant nature of smelling salts means that they can exacerbate any pre-existing cervical spine injury by causing reflex withdrawal away from them, although this has been found to be a result of holding the smelling salts closer to the nose than recommended.

References

{{Reflist Ammonium compounds First aid