Dog Ate a Penny: Zinc Poisoning and Blockage Risks

Name: Dog Ate a Penny: Zinc Poisoning and Blockage Risks
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-03

What happens if a dog eats a penny depends almost entirely on when that penny was made. Pennies minted after 1982 are mostly zinc, and zinc can poison a dog within hours. Older copper pennies are far less dangerous, though any coin can still lodge in the gut and cause a blockage. This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

A penny minted after 1982 is about 97.5% zinc, and zinc dissolves in stomach acid, so it can poison your dog even if it never blocks the intestine.
Call your veterinarian right away, or call the ASPCA Animal Poison Control Center at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661.
Do not induce vomiting unless a veterinarian tells you to. A coin can damage the esophagus on the way back up.
Watch for vomiting, lethargy, pale gums, yellow eyes, dark urine, or a sudden collapse. These can appear within hours to a couple of days.
Pennies usually need to come out, either by endoscopy or surgery. Waiting to see if it passes is not safe with a zinc penny.

Is a Penny Actually Toxic to Dogs?

Yes, if it was minted after 1982. In a review of 55 dogs with confirmed zinc poisoning from metal objects, US pennies minted after 1982 were the most common source, accounting for 67.3% of cases [1]. That single fact explains why veterinarians treat a swallowed penny as an emergency and not a wait-and-see situation.

Pennies made before 1982 are mostly copper with only trace zinc. Copper is not harmless in large amounts, but a single older penny is much less likely to cause poisoning. The bigger concern with those is physical, meaning the coin could still get stuck.

Other zinc sources exist too. Hardware like nuts, bolts, and screws, some zippers and board game pieces, and certain topical creams such as diaper rash ointment all contain zinc [2][3]. If your dog chewed a tube of rash cream, that is a different exposure but the same mineral. You can read more about swallowed objects in general in our guide to My Dog Ate a Pen: Is It Toxic or Just a Blockage Risk?.

Why Post-1982 Pennies Are the Real Problem

The US Mint changed the penny's composition in 1982. The core became zinc with a thin copper plating. That plating is soft and wears through quickly in stomach acid, which exposes the zinc underneath.

Zinc is an essential nutrient. Dogs need small amounts to stay healthy [2][3]. The problem is dose. A penny holds far more zinc than a dog's body can handle, and the stomach is very good at pulling it into the bloodstream.

What Zinc Does Inside Your Dog's Body

Once the penny sits in the stomach, acid breaks down the zinc and it gets absorbed into the blood [2][4]. From there, it damages red blood cells and can harm the kidneys, liver, and heart [2][3].

The red blood cell damage is the headline problem. Zinc toxicosis causes hemolytic anemia, meaning red blood cells burst faster than the body can replace them. In the 55-dog review, anemia was the most common consequence, affecting 87% of cases [1]. Acute liver injury followed at 82%, coagulopathy (a bleeding problem) at 71%, acute kidney injury at 26.9%, and acute pancreatitis at 5.5% [1].

A newer case report described a dog with zinc poisoning who also developed methemoglobinemia, a condition where red blood cells cannot carry oxygen properly [5]. The dog developed multi-organ dysfunction and ultimately went into cardiopulmonary arrest [5]. This was the first reported case of its kind, so researchers are still working out how often it happens and whether it changes outcomes [5].

Blockage Is a Separate Risk

Even a copper penny can cause a mechanical obstruction. A coin that will not move through the intestines can block the tract and damage the tissue, and surgery may be needed to remove it [4]. Foreign bodies in the stomach and esophagus are common in dogs, and small breeds are especially prone to objects lodging in the esophagus [6].

Blockage and poisoning often happen together with pennies. The coin sits in one spot, keeps releasing zinc, and the dog gets sicker while the coin stays put.

Signs of Zinc Poisoning and Blockage in Dogs

Signs can start within hours of ingestion, or they can take a day or two to show up. In the 55-dog review, the median time from ingestion to arriving at the hospital was 48 hours for dogs who survived and for those who did not [1]. That means many owners did not realize anything was wrong until the dog had been sick for two days.

Watch for these signs:

Vomiting, sometimes with blood
Loss of appetite
Lethargy or weakness
Pale gums, which point to anemia
Yellow tint to the gums, eyes, or skin (jaundice)
Dark, brownish, or reddish urine
Fast breathing or a fast heart rate
Collapse
Abdominal pain, pacing, or a hunched posture
Diarrhea or black, tarry stool

Some of these signs overlap with simple stomach upset. That overlap is exactly why a swallowed penny needs a professional opinion instead of a judgment call at home. If your dog swallowed something soft instead, our article on Dog Ate a Sponge: Signs of Blockage and What to Do covers that scenario.

How Fast Do Signs Appear?

Timing varies with the dog's size, the number of coins, and how long the coin has been in the stomach. Small dogs get sick faster because the same amount of zinc is a larger dose for a smaller body. A single penny can cause serious illness in a Chihuahua while a Great Dane might take longer to show the same effects.

Do not use size as a reason to wait. Call either way.

What to Do Right Now

Call your veterinarian, an emergency clinic, the ASPCA Animal Poison Control Center at (888) 426-4435, or Pet Poison Helpline at (855) 764-7661. Do this even if your dog seems completely normal. Zinc poisoning is treatable when it is caught early and much harder to manage once red blood cells are destroyed.

Do not induce vomiting unless a veterinarian tells you to. Coins can scrape or tear the esophagus on the way up, and vomiting does not remove a coin that has already moved into the stomach or beyond.

Gather what you know before you call:

How many coins, and roughly when they were swallowed
Whether the pennies were minted after 1982
Your dog's weight and any health conditions
Any medications your dog takes

If you still have the coin wrapper, a piggy bank, or a matching penny from the same jar, bring one with you. Knowing the mint year helps your vet plan treatment.

Do not feed your dog a large meal to "cushion" the coin, and do not give home remedies. Your veterinarian will decide what happens next.

How Veterinarians Diagnose and Treat a Swallowed Penny

Your vet will start with a physical exam and questions about timing. X-rays are the usual next step. Pennies show up clearly on radiographs, and the images tell your vet where the coin is sitting and whether there are multiple coins.

Blood work matters just as much. Your vet will check the red blood cell count, liver values, kidney values, and clotting times. These tests show how much damage the zinc has already done and give a baseline for tracking improvement.

Removing the Coin

The coin has to come out. That is the core of treatment, because zinc keeps leaching into the blood as long as the penny stays in the stomach.

If the coin is still in the stomach, many vets use endoscopy, a scope passed down the throat, to grab and remove it without surgery. If the coin has moved into the intestines or is causing an obstruction, surgery may be needed [4]. In the 55-dog review, 83% of dogs reached a stable red blood cell level within a median of 24 hours after the metal object was removed [1].

Supportive Care

Removal is only part of the plan. Many dogs need intravenous fluids, medications to protect the stomach, and monitoring for heart and kidney problems. In that same review, 67.3% of dogs needed blood products [1]. Some dogs need oxygen support or treatment for clotting problems.

Your veterinarian calculates every medication dose from your dog's weight and current health. There is no at-home dose for this situation.

Outlook After Zinc Poisoning

The outlook depends on how quickly the coin comes out and how much damage happened first. In the 55-dog review, 81.8% of dogs survived and 18.2% died or were euthanized [1]. Survivors and non-survivors had the same median illness duration before arriving at the hospital, which suggests that how sick the dog is at presentation matters more than how long the coin was there [1].

Median hospitalization was 3 days for both groups [1]. Some dogs go home sooner, and some need longer stays.

Dogs who survive often recover well once the zinc source is gone and their blood counts stabilize. Your vet will likely want follow-up blood work to confirm the anemia and organ values are returning to normal.

Prevention and Safer Alternatives

The simplest prevention is keeping coins out of reach. That means no loose change on nightstands, coffee tables, floors, or in low drawers. Dogs are quick, and a penny on the carpet looks a lot like a treat.

Other steps that help:

Check pockets before doing laundry, since coins fall out of pants and land on the floor
Keep piggy banks, coin jars, and change purses above counter height
Store hardware like screws, bolts, and nuts in closed containers
Keep diaper rash creams and zinc-containing ointments in a closed cabinet [2][3]
Teach "drop it" and "leave it" so you have a tool when something hits the floor
Supervise your dog around craft supplies, board games, and remote controls

If your dog has a habit of eating non-food items, talk with your vet about it. Repeated foreign body ingestion is a pattern worth addressing, and it raises the odds of a future obstruction. Our guide to My Dog Ate a Toy: How to Tell If It Will Pass or Cause a Blockage walks through that decision process.

Limitations and When to Contact a Veterinarian

No article can tell you whether your specific dog swallowed a zinc penny, how much zinc has been absorbed, or whether the coin is moving. That requires an exam, imaging, and blood work. Individual cases need a veterinarian.

Call the same day if your dog swallowed a penny and is still acting normal. Timing matters, and early removal is easier than treating advanced anemia.

Go to an emergency clinic now if you see any of these:

Repeated vomiting or vomiting blood
Pale, white, or yellow gums
Collapse, weakness, or trouble breathing
Dark or bloody urine
A distended, painful abdomen
Seizures or unresponsiveness

Call your vet for a routine visit if your dog swallowed a penny days ago and seems fine, or if you are not sure whether a coin was actually swallowed. An exam and X-ray can settle the question.

Frequently Asked Questions

Can a penny pass through a dog on its own?

Sometimes, but you cannot count on it. Some coins pass through the stool without causing problems, while others release enough zinc to poison the dog [2][3]. Because you cannot tell which will happen, a swallowed penny always needs a vet call.

Are all pennies dangerous, or only newer ones?

Pennies minted after 1982 are the main concern because they are mostly zinc [1]. Older copper pennies carry much less zinc, but they can still cause a blockage if they get stuck [4]. Treat any swallowed coin as a reason to call your vet.

How long after eating a penny would my dog get sick?

Signs can appear within hours, but many dogs are not brought in until about two days later [1]. That delay is common because early signs look like ordinary stomach upset. Do not wait for symptoms to confirm the problem.

Will my dog need surgery to remove the penny?

Not always. If the coin is still in the stomach, many vets remove it with an endoscope instead of surgery. Surgery is more likely if the coin has moved into the intestines or is causing an obstruction [4]. Your vet will decide based on imaging.

Can I just watch my dog at home and check the stool?

No. Zinc poisoning can damage red blood cells, the liver, the kidneys, and the heart before you notice anything wrong [2][3][5]. By the time signs are obvious, your dog may already need blood products or intensive care [1]. Call your vet or a poison control line instead of waiting.

References

Retrospective evaluation of the clinical course and outcome of zinc toxicosis due to metallic foreign bodies in dogs (2005-2021): 55 cases. Journal of veterinary emergency and critical care (San Antonio, Tex. : 2001), 2023.
Is Zinc Poisonous for Dogs. Pet Poison Helpline.
Is Zinc Toxic to Dogs. Pet Poison Helpline.
My Dog Ate Metal What Should I Do. Pet Poison Helpline.
Methemoglobinemia Secondary to Zinc Foreign Body Ingestion in a Dog. Journal of veterinary emergency and critical care (San Antonio, Tex. : 2001), 2026.
Prevalence and characteristics of foreign body-induced upper gastrointestinal obstruction in dogs. Journal of advanced veterinary and animal research, 2025.