So SilverThistle posted about smelling salts in the book she's reading - her grandmother had an old bottle which she couldn't resist smelling. (I would have done this too.) I then became interested in smelling salts, so of course you know what I did.
wikipedia: smelling salts
The definition, explaining why the smell is so awful/powerful:
Smelling salts, also known as spirit of hartshorn or sal volatile, are chemical compounds used for arousing consciousness. The usual active compound is ammonium carbonate, a colorless-to-white, crystalline solid ((NH4)2CO3). Because most modern solutions are mixed with water, they should more properly be called "aromatic spirits of ammonia." Modern solutions may also contain other products to perfume or act in conjunction with the ammonia, such as lavender oil or eucalyptus oil.
And then the part I was entirely clueless to - these are still in use today:
Smelling salts are often used on athletes (such as boxers) when they are knocked unconscious or semi-conscious to arouse consciousness and restore mental alertness.
They are also used in competitions (such as powerlifting, strong man and ice hockey) to "wake up" competitors to perform better. Famous athletes such as Alexander Ovechkin, Tyler Seguin, Brett Favre, Peyton Manning, Carlos Boozer, Samuel Eto'o, and Tom Brady have been seen using smelling salts on the sidelines.
From one of the cited articles:
By Mike Freeman, The Florida Times-Union, February 3, 2005
"...During an October game against Detroit, television cameras caught Favre raising a white capsule to his nose and taking two small, short breaths.
...The capsule, just several inches long, was clearly identifiable as an ammonia cartridge, with its ingredient of adrenaline-pumping ammonia. Favre declined comment for this story.
Neither illegal nor against the rules of the NFL or NCAA, an increasing number of professional and college players are using ammonia sniffing as a way to pep themselves up for the rigors and violence of the sport.
Hundreds of players, from the Jaguars to the Packers to the University of Florida, from high-profile pass throwers to the grunts on kickoff coverage, inhale dozens, sometimes even hundreds, of doses a week in practices and games, a season-long investigation by The Florida Times-Union has discovered.
...Strahan said he uses the capsules to clear his sinuses, "but there is no question that you get a high after doing them. It's not like you get the munchies afterwards, but they are a great pick-me-up. They help you get ready for the game."