ammonium carbonate, sometimes with added perfume, that is sniffed as a mild stimulant and to relieve fainting
A bottle of smelling salts contains a chemical with a strong smell which is used to help someone recover after they have fainted. a strong-smelling chemical that you hold under someone's nose to make them conscious again when they have fainted
An aromatic preparation of carbonate of ammonia and, often, some scent, to avoid or relieve faintness, headache, or the like