Why
Plain cooked potato is not toxic to dogs. The AKC says plain mashed or soft cooked potatoes are fine in small amounts, and many dogs like them. Potato is mostly starch, so it adds calories without much else a dog needs.
Holiday mashed potatoes are a different dish. They are usually made with butter, milk or cream and salt, and sometimes cheese, garlic, onion or chives. The AKC warns that a lot of butter can trigger pancreatitis, and garlic, onion and chives can damage a dog's red blood cells. Green potatoes contain solanine, a natural toxin, and raw potato is hard to digest.
Risks to watch for
- Butter, cream and cheese, which make the dish rich and fatty
- Garlic, onion, chives or garlic powder
- Salt and gravy
- Green potatoes, sprouts and raw potato
- Instant mashed potato mixes with added flavorings
- Weight gain, especially in dogs that are overweight or diabetic
How to share safely
- Set aside a few pieces of plain boiled or baked potato before you add butter, milk or seasoning.
- Mash them with a little of the cooking water instead of milk or butter.
- Cut away any green patches, and throw out potatoes that are green or sprouting.
- Mix a spoonful into your dog's regular food rather than serving a bowlful.
How much?
Small dogs can have about a teaspoon of mashed potatoes and large dogs a tablespoon or two, now and then.
Which mashed potato add-ins are the problem?
The potato is rarely the issue. What goes into the pot is. Here is how the usual extras stack up:
- Butter and cream: very fatty. A rich spoonful is not the same as a plain one, and fatty food is linked to pancreatitis.
- Milk: many adult dogs digest lactose poorly and may get gas or diarrhea.
- Cheese and sour cream: more fat and salt.
- Garlic, including roasted garlic and garlic powder: damages red blood cells, and powder is concentrated.
- Onion, chives and scallions: members of the same family as garlic, with the same risk.
- Gravy: fatty and salty, and often made with onion.
- Bacon bits: salty and fatty.
Green potatoes, sprouts and raw potato
When potatoes are exposed to light, some varieties develop green patches, which the AKC says indicate more solanine. Sprouts, and the leaves and stems of potato plants in the garden, are also a source. Solanine can cause vomiting, diarrhea, lethargy and muscle weakness. Contact your vet if your dog shows these after eating green potatoes or potato plants.
Raw or half-cooked potato is hard to digest, and chunks can be a choking hazard. Always cook potato until it is soft all the way through, and store potatoes in a dark place your dog cannot reach.
Fries, chips, potato skins and other potato dishes
French fries and potato chips are fried and salted, and many flavored chips use onion or garlic powder. A couple are unlikely to cause harm, but a bag or a plate of them is a lot of fat and salt for a dog.
Loaded potato skins, scalloped potatoes and potatoes au gratin come with cheese, cream, bacon and often onion. Potato salad usually has mayonnaise and onion. The AKC adds that plain potato will not cause diabetes, but dogs with diabetes or a weight problem still need their portions controlled, so ask your vet before adding starchy foods to their meals.
Common questions
Are mashed potatoes good for dogs?
Only in limited ways. Plain cooked potato is not toxic to dogs. The AKC says plain mashed or soft cooked potatoes are fine in small amounts, and many dogs like them.
Are mashed potatoes bad for dogs?
It can be. Risks to watch for: butter, cream and cheese, which make the dish rich and fatty; garlic, onion, chives or garlic powder.
Are dogs allowed to have mashed potatoes?
Only in small amounts and the right form. Set aside a few pieces of plain boiled or baked potato before you add butter, milk or seasoning.
Sources
- Merck Veterinary Manual. Pancreatitis in Dogs and Cats.
- ASPCA Animal Poison Control Center. People Foods to Avoid Feeding Your Pets.
- Merck Veterinary Manual. Toxicology section.
- American Kennel Club (AKC). “Can Dogs Eat…?” article series.
If your dog has eaten something toxic, contact your veterinarian or an emergency animal hospital right away. Do not wait for symptoms. In the US you can also call the ASPCA Animal Poison Control Center at (888) 426-4435 or the Pet Poison Helpline at (855) 764-7661 (fees may apply).