by 
Smelling salts have been used for centuries to keep people awake. They were once prominent at funeral homes and at blood donation drives. Athletes inhale them from the sidelines in hopes of improving their performance. Rocky takes a whiff of a smelling salt to get back in the ring and continue the fight. But how do these smelling salts work?
Smelling salts contain ammonia, a strong and smelly chemical, said Dr Anthony Alessi (opens in new tab)a clinical professor of neurology and orthopedics at the University of Connecticut.
The ammonia gas irritates the membranes in the nose and throughout Respiratory system and causes an inhalation reflex, according to a 2006 study i British Journal of Sports Medicine (opens in new tab). The inhalation reflex changes breathing patterns, increases oxygen flow and gas exchange and can thereby increase alertness in certain situations, the study authors wrote.
Related: Why does cannabis smell fishy?
Although ammonia can be toxic if ingested in large quantities, a whiff of these salts is safe. But that may not always be very useful, Alessi said.
While it was once common to use smelling salts to keep athletes conscious after a concussion, this has fallen out of practice because it can be dangerous, Alessi said. It is a reflex to move away from a noxious smell; if an athlete has a head or neck injury, the sudden smell can make them flinch and aggravate the injury.
Athletes sometimes still use a scent of smelling salts in an attempt to improve their performance. While the exercise may make them feel more alert and focused, there is no evidence that it actually improves muscle strength, according to a 2014 study in Journal of Exercise Physiology (opens in new tab).
It’s also important to note that if a person faints or their consciousness wavers, it’s because the brain doesn’t have everything it needs. It may lack energy or oxygen, so it restarts, Alessi said. This can happen in all kinds of situations, like when people pass out while watching gory movies or when people with diabetes fainting due to low blood sugar. In the past, people have rushed to smelling salts because it feels like they are doing something about the unconsciousness.
But in reality, fainting is often a protective mechanism that points to a larger problem that may need medical attention. So stopping it with smelling salts is not really a solution. “The brain is very resilient,” Allessi said, and it protects and revives itself.
This article is for informational purposes only and is not intended to provide medical advice.
