Also called: ammonia inhalants (Show more) smelling salts, any of several different preparations of ammonia-based product and other ingredients used to revive a person affected by syncope (fainting). Historically, smelling salts contained ammonium carbonate and perfume; modern preparations typically consist of ammonia dissolved in water and ethanol, sometimes infused with a scented oil, such as eucalyptus. The salts release ammonia gas that irritates the nose and lung membranes, triggering an inhalation reflex, which prompts the muscles that control breathing to work faster and helps restore oxygen flow to the brain and body. Ammonium chloride, the salt of ammonia and hydrogen chloride, has been known since at ...(100 of 568 words) Access the full article Help support true facts by becoming a member. Subscribe today!