Smelling salts

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Two capsules of smelling salts from a first-aid kit. A thin inner glass tube contains alcohol and ammonia; the outer layer is cotton and netting. When crushed, the liquid is released into the cotton, while the glass shards are retained inside. The ammonia-soaked cotton is waved in front of the nose for the treatment of fainting. First aid ammonia inhalant capsules.jpg
Two capsules of smelling salts from a first-aid kit. A thin inner glass tube contains alcohol and ammonia; the outer layer is cotton and netting. When crushed, the liquid is released into the cotton, while the glass shards are retained inside. The ammonia-soaked cotton is waved in front of the nose for the treatment of fainting.

Smelling salts, also known as ammonia inhalants, spirit of hartshorn or sal volatile, are chemical compounds used as stimulants to restore consciousness after fainting. [1]



The usual active compound is ammonium carbonate—a colorless-to-white, crystalline solid ((NH4)2CO3). [1] Because most modern solutions are mixed with water, they should properly be called "aromatic spirits of ammonia". [1] Modern solutions may also contain other products to perfume or act in conjunction with the ammonia, such as lavender oil or eucalyptus oil. [2]

Historically, smelling salts have been used on people feeling faint, [3] [4] [5] 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. [1]

They are also used as a form of stimulant in athletic competitions (such as powerlifting, strong man and ice hockey) to "wake up" competitors to perform better. [1] [6] In 2005, Michael Strahan estimated that 70–80% of National Football League players were using smelling salts as stimulants. [7]


Flask with smelling salts, used for reviving dental patients after a procedure. French, 18th century. M0354 1951-23-102 2.jpg
Flask with smelling salts, used for reviving dental patients after a procedure. French, 18th century.

Smelling salts have been used since Roman times and are mentioned in the writings of Pliny as Hammoniacus sal. [1] Evidence exists of use in the 13th century by alchemists as sal ammoniac. [1] In the 14th-century "The Canon's Yeoman's Tale" one of Chaucer's The Canterbury Tales , an alchemist purports to use sal armonyak. [8] 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. [1]

They were widely used in Victorian Britain to revive fainting women, and in some areas constables would carry a container of them for the purpose. [9] 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. [10] [11] 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 to keep smelling salts in their first aid boxes. [12]

Physiological action

Rembrandt's Unconscious Patient (Allegory of Smell) shows a woman using smelling salts to revive a man who has fainted at the hands of a barber-surgeon. Rembrandt-SMELL.jpg
Rembrandt's Unconscious Patient (Allegory of Smell) shows a woman using smelling salts to revive a man who has fainted at the hands of a barber-surgeon.

Solid ammonium carbonate and ammonium bicarbonate salts partly dissociate to form NH
, CO
and H
vapour as follows:

(NH4)2CO3 → 2 NH3 + CO2 + H2O
NH4HCO3 → NH3 + CO2 + H2O

The smelling salts release ammonia (NH
) gas, which triggers an inhalation reflex. It causes the muscles that control breathing to work faster by irritating the mucous membranes of the nose and lungs. [6]

Fainting can be caused by excessive parasympathetic and vagal activity that slows the heart and decreases perfusion of the brain. [13] The sympathetic irritant effect is exploited to counteract these vagal parasympathetic effects and thereby reverse the faint. [14]


Ammonia gas is toxic in large concentrations for prolonged periods and can be fatal. [1] [5] 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 10–15 centimetres (4–6 in). [1]

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, [1] such as after concussions when hospitalization may be advisable, and some governing bodies recommend specifically against it. [15] 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. [1]

Related Research Articles

<span class="mw-page-title-main">Ammonia</span> Chemical compound made of nitrogen and hydrogen

Ammonia is a compound of nitrogen and hydrogen with the formula NH3. A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45 percent of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. It is estimated that around 40% of the nitrogen in human beings originally comes from industrial ammonia production. As such, its importance can hardly be overstated.

In organic chemistry, amines (, UK also ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (NH3), wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group (these may respectively be called alkylamines and arylamines; amines in which both types of substituent are attached to one nitrogen atom may be called alkylarylamines). Important amines include amino acids, biogenic amines, trimethylamine, and aniline; see Category:Amines for a list of amines. Inorganic derivatives of ammonia are also called amines, such as monochloramine (NClH2).

In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively charged sodium ions and negatively charged chloride ions.

Ammonium Polyatomic ion

The ammonium cation is a positively charged polyatomic ion with the chemical formula [NH4]+. It is formed by the protonation of ammonia. Ammonium is also a general name for positively charged or protonated substituted amines and quaternary ammonium cations, where one or more hydrogen atoms are replaced by organic groups.

Sodium carbonate Chemical compound

Sodium carbonate, Na2CO3, (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions in water. Historically, it was extracted from the ashes of plants growing in sodium-rich soils. Because the ashes of these sodium-rich plants were noticeably different from ashes of wood (once used to produce potash), sodium carbonate became known as "soda ash". It is produced in large quantities from sodium chloride and limestone by the Solvay process.

Ammonium chloride Chemical compound

Ammonium chloride is an inorganic compound with the formula NH4Cl and a white crystalline salt that is highly soluble in water. Solutions of ammonium chloride are mildly acidic. In its naturally occurring mineralogic form, it is known as sal ammoniac. The mineral is commonly formed on burning coal dumps from condensation of coal-derived gases. It is also found around some types of volcanic vents. It is mainly used as fertilizer and a flavouring agent in some types of liquorice. It is the product from the reaction of hydrochloric acid and ammonia.

Ammonium bicarbonate Chemical compound

Ammonium bicarbonate is an inorganic compound with formula (NH4)HCO3. The compound has many names, reflecting its long history. Chemically speaking, it is the bicarbonate salt of the ammonium ion. It is a colourless solid that degrades readily to carbon dioxide, water and ammonia.

Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although the name ammonium hydroxide suggests an alkali with composition [NH+
, it is actually impossible to isolate samples of NH4OH. The ions NH+
and OH do not account for a significant fraction of the total amount of ammonia except in extremely dilute solutions.

The Solvay process or ammonia-soda process is the major industrial process for the production of sodium carbonate (soda ash, Na2CO3). The ammonia-soda process was developed into its modern form by the Belgian chemist Ernest Solvay during the 1860s. The ingredients for this are readily available and inexpensive: salt brine (from inland sources or from the sea) and limestone (from quarries). The worldwide production of soda ash in 2005 was estimated at 42 million tonnes, which is more than six kilograms (13 lb) per year for each person on Earth. Solvay-based chemical plants now produce roughly three-quarters of this supply, with the remaining being mined from natural deposits. This method superseded the Leblanc process.

Hartshorn Antler of male red deer

Hartshorn is the antler of male red deer.

Carbamate Salt or ester of carbamic acid or N-substituted carbamic acid

A carbamate is a category of organic compounds that is formally derived from carbamic acid (NH2COOH). The term includes organic compounds (e.g., the ester ethyl carbamate), formally obtained by replacing one or more of the hydrogen atoms by other organic functional groups; as well as salts with the carbamate anion H
(e.g. ammonium carbamate).

Ammonium carbonate Chemical used as leavening agent and smelling salt

Ammonium carbonate is a salt with the chemical formula (NH4)2CO3. Since it readily degrades to gaseous ammonia and carbon dioxide upon heating, it is used as a leavening agent and also as smelling salt. It is also known as baker's ammonia and was a predecessor to the more modern leavening agents baking soda and baking powder. It is a component of what was formerly known as sal volatile and salt of hartshorn, and produces a pungent smell when baked.

Classical qualitative inorganic analysis is a method of analytical chemistry which seeks to find the elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution, therefore materials in other forms may need to be brought to this state before using standard methods. The solution is then treated with various reagents to test for reactions characteristic of certain ions, which may cause color change, precipitation and other visible changes.

Ammonium sulfate Chemical compound

Ammonium sulfate (American English and international scientific usage; ammonium sulphate in British English); (NH4)2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen and 24% sulfur.

Manganese(II) carbonate Chemical compound

Manganese carbonate is a compound with the chemical formula MnCO3. Manganese carbonate occurs naturally as the mineral rhodochrosite but it is typically produced industrially. It is a pale pink, water-insoluble solid. Approximately 20,000 metric tonnes were produced in 2005.

<span class="mw-page-title-main">Ammonium acetate</span> Chemical compound

Ammonium acetate, also known as spirit of Mindererus in aqueous solution, is a chemical compound with the formula NH4CH3CO2. It is a white, hygroscopic solid and can be derived from the reaction of ammonia and acetic acid. It is available commercially.

Barium chlorate Chemical compound

Barium chlorate, Ba(ClO3)2, is the barium salt of chloric acid. It is a white crystalline solid, and like all soluble barium compounds, irritant and toxic. It is sometimes used in pyrotechnics to produce a green color. It also finds use in the production of chloric acid.

Ammonium cyanide Chemical compound

Ammonium cyanide is an unstable inorganic compound with the formula NH4CN.

<span class="mw-page-title-main">Ammonium carbamate</span> Chemical compound

Ammonium carbamate is an organic compound with the formula [NH4][H2NCO2] consisting of ammonium cation NH+4 and carbamate anion NH2COO. It is a white solid that is extremely soluble in water, less so in alcohol. Ammonium carbamate can be formed by the reaction of ammonia NH3 with carbon dioxide CO2, and will slowly decompose to those gases at ordinary temperatures and pressures. It is an intermediary in the industrial synthesis of urea (NH2)2CO, an important fertilizer.


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