Smelling salts are a mixture of chemicals, typically containing ammonia, that can revive individuals who have fainted. The ammonia and ammonium compounds in smelling salts have a repulsive, sharp odor that is similar to that of many household cleaners. The aroma can be described as sharp, strong, and slightly sweet, with a medicinal feel. The fumes from smelling salts are harsh and irritate the interior of the nose, causing the lungs to quickly breathe deeply to clear the nasal passage. When held up to someone’s nose, the fumes irritate the interior of the nose, and overuse of smelling salts may lead to damage to the nasal passages. Some uncommon side effects of smelling salts include coughing, difficulty breathing, headache, vomiting, and diarrhea. When a person is resuscitated with smelling salts, they may reflexively jerk their head and neck as they attempt to move away from the ammonia fumes, which can further injure someone if they fainted due to a head injury.