Evidence supporting the use of: Ammonia
For the health condition: Fainting
Synopsis
Source of validity: Traditional
Rating (out of 5): 2
Ammonia, commonly delivered as "smelling salts" (ammonium carbonate and perfume), has a long history of use in reviving individuals who have fainted or lost consciousness. The practice is primarily rooted in tradition, dating back to at least the 17th century. The rationale behind its use stems from ammonia’s strong, irritating odor, which stimulates the mucous membranes of the nose and lungs, inducing an inhalation reflex. This reflex can trigger a brief increase in respiratory rate, heart rate, and alertness, theoretically helping to arouse someone who has fainted due to a vasovagal episode (sudden drop in heart rate and blood pressure).
However, the scientific evidence supporting ammonia’s efficacy for treating fainting is limited and largely anecdotal. Few controlled studies exist, and those that do generally conclude that while smelling salts may provoke a rapid arousal response, they do not address underlying causes of syncope, nor do they provide any lasting benefit. Modern medical guidelines do not recommend ammonia inhalants for syncope management, and some authorities warn that they may be harmful, particularly in those with respiratory conditions or certain cardiac problems. Thus, while ammonia’s use is justified by tradition and there is some physiological plausibility, evidence for its effectiveness is weak.