Why it's dangerous
When ingested, the acidic environment of the stomach breaks down the zinc, which is then absorbed into the bloodstream, causing red blood cell destruction and organ damage.
Toxic compound: Zinc
Good to know
While some coins pass safely, zinc-containing pennies are potentially fatal if not treated; other sources include galvanized hardware and diaper rash creams.
Sources
This page is informational and is not veterinary advice. If your pet has been exposed to something risky, contact your vet or an animal poison control line right away.