Pennies made after 1982 have a zinc core. This heavy metal can be toxic to dogs, leading to hemolytic anemia, blood in the urine, and possible kidney failure. If you see your dog ingest pennies, induce vomiting. Many times, clinical signs do not show up for days, as the stomach acid dissolves the metal. Surgery to remove any pennies may be required and your dog may need hospitalization for fluids and to attempt therapy to chelate (remove from the body) the zinc.