Can Dogs Eat Cooked Onions? (The Risks!)

No, dogs cannot eat cooked onions.

Cooked onions aren’t any less toxic than raw, non-cooked onions.

Onions contain N-propyl disulfide and N-propyl trisulfide, which interferes with a dog’s red blood cell’s ability to carry oxygen.

This results in a condition called Heinz body anemia, where the cells become fragile and can break down or clump together.

Which explains why onions cause dogs to vomit, have diarrhea, become drowsy and lethargic.

In severe cases, onions can cause a dog to go into shock, develop a problem with its central nervous system or even die.

Onions also contain a toxin called thiosulphate which causes red blood cells to take on an abnormal shape causing a condition called a hemolytic anemic syndrome.

This results in damage to the central nervous system, liver, or kidneys which can result in death.

Can dogs eat cooked onions in meatloaf?

No, they cannot.

Even though cooking them may take away some of the properties that cause Heinz body anemia, it doesn’t change the fact that onions are still toxic to dogs.

Can dogs eat cooked onions and celery?

No, dogs cannot eat cooked onions and celery. Cooked vegetables still contain thiosulphate which has the potential to damage a dog’s central nervous system, liver, or kidneys.

Can dogs eat cooked sweet onions?

No, dogs cannot eat cooked sweet onions. They contain a toxin called thiosulphate which is still toxic to them even though it is cooked.

Can dogs eat cooked spring onions?

The short answer is no, dogs cannot eat cooked spring onions. Although they may not be as dangerous as raw ones, they still contain toxic properties that are still harmful to dogs.

What should I feed my dog instead?

If you are looking for an alternative to onion scraps, here are the top 3 vegetables that dogs can eat:

  1. Green beans – low in fat, sources of carbohydrates and protein
  2. Carrots – high in fiber, beta-carotene (precursor to vitamin A), low in calories, rich source of calcium and phosphorous, can help with dental health
  3. Sweet potatoes – good source of carbohydrates, beta-carotene (precursor to vitamin A), potassium, contains vitamin E and C


Cooked onions are still toxic to dogs. It doesn’t matter if they’re cooked or not, the onion will cause your dog to vomit, have diarrhea and become lethargic. If you notice any of these symptoms in your pet then it is imperative that you take them immediately to a veterinarian who can assess their condition and prescribe treatment for whatever illness they may be suffering from.