Toxicity
Zinc, a major component of post-1982 US cents, is toxic in large quantities. Swallowing such a coin, which is 97.5% zinc, can cause damage to the stomach lining because of the high solubility of the zinc ion in the acidic stomach. Coins are the most commonly ingested foreign body in children but generally are allowed to pass spontaneously unless the patient is symptomatic. Zinc toxicity, mostly in the form of the ingestion of US pennies minted after 1982, is commonly fatal in dogs where it causes a severe hemolytic anemia. It is also highly toxic in pet parrots and can often be fatal.
Read more about this topic: Penny (United States Coin)