Eating a small amount of rock salt may cause redness around the mouth, rash or drooling, but it usually doesn't cause any serious problems, according to National Capital Poison Center. Consuming a large amount of rock salt can lead to sodium poisoning, which causes seizures, coma and possibly death.
Individuals who swallow rock salt should rinse their mouths and drink a small amount of milk or water, according to National Capital Poison Center. Poison Control should be contacted immediately for further instructions. If an individual is unconscious, not breathing or is having seizures after swallowing rock salt, emergency medical attention is necessary.