The NFL is banning the use of “smelling salts” during games, saying the products aren’t proven to be safe and also could mask signs of a concussion. The league sent a memo to teams on Tuesday explaining the decision to ban smelling salts and any other ammonia inhalant during pregame activities, games and halftime on the sideline or locker rooms.

The NFL announced in a memo issued Tuesday that they have banned ammonia inhalants, prohibiting teams from providing players with ammonia inhalers, capsules, "smelling salts" or ammonia in a cup. The prohibition applies throughout all NFL games and applies to all team personnel,