Tap to Read ➤

Are Onions Bad for Dogs?

Mubasherin Sayed
There are many food items which are considered inappropriate for dogs, and onions come in this list. Containing certain compounds that can be toxic for our furry friends, onions should be avoided in any dog's diet. Read this piece to know more about why onions are bad for dogs.
Yes, it is a fact that onions are definitely bad for dogs, irrespective of whether they are cooked, raw, or even dehydrated. A common ingredient in our cooking and the food that we eat on a daily basis, onions can actually prove to be lethal for dogs.
One of the common mistakes that most dog owners tend to make, is to assume that onions, only in the raw form, are bad for their dogs, but unfortunately, this theory is not at all true.

These toxins can make their way into a dog's system by means of fried onion rings, onion seasonings, tomato sauce, pizzas, salad dressings, burgers, and other processed foods.
Even some baby foods contain onions in the powdered form, and when these are consumed in large amounts, it can be extremely deadly for the dog. So why exactly are onions dangerous for dogs? This is because, onions cause toxicosis, or in simple terms, poisoning in dogs.
Onion Poisoning in Dogs

Onions, garlic, chives and leeks are some plants that belong to the allium family. It contains a distinct aroma that imparts the food with a delicious smell. Unfortunately, when it concerns your pet dog, onions and others plants in the same family can be dangerous due to the presence of organosulfur compounds like thiosulphate.
These compounds, which impart the flavor and aroma to the onions, enter the gastrointestinal tract of the dog. Due to the absence of any enzymes that can digest these compounds in the dog's GI tract, they tend to accumulate, thus causing onion toxicosis.
The presence of large amounts of thiosulphate in the blood can lead to the oxidation of hemoglobin, which is the oxygen-carrying proteins in the red blood cells of the dog. Once this happens, the hemoglobin in the canine's blood can form small clumps known as Heinz bodies, that get attached to the cell membranes.
Although the Heinz bodies in itself are not dangerous, they can weaken the cell membranes and lead to red blood lysis. The loss of red blood cells in the blood causes a form of anemia that is known as hemolytic anemia or Heinz body anemia. Another compound in onions that damages red blood cells is allyl propyl disulfide, a component of onion oil.
Note: Cooking has no effect on onions, and pieces of cooked onions or onion powder in the food is as fatal to dogs as raw onions are.

When are Onions Toxic for Dogs?

Onions are fatal for dogs if they consume it in very large quantities.
If the dog has round 600 to 800 grams of onions in one meal, then you would start noticing the tell-tale symptoms of onion poisoning. It is important to note that the symptoms can range from mild to severe, depending upon the breed of the dog. So, a large dog breed will suffer from the lesser severe symptoms as compared to a smaller dog.
So do you stop feeding your dogs pizzas, burgers or table scarps? Ideally, you should, as even small quantities of onions (150 grams) on a regular basis can lead to onion toxicosis, in around 24 hours.

Note: Onions can be toxic in the long run even when fed in small quantities.
How to Identify Onion Poisoning in Dogs?

You need to watch out for symptoms of onion indigestion and poisoning in dogs. These include:
  • Lethargy
  • Discolored urine
  • Vomiting
  • Diarrhea
  • Inflammation of the skin
  • Decreased appetite
  • Dark-colored urine
  • Yellowing of the skin and whites of the eyes
  • Bluish or pale gums
  • Fast heart rate and breathing rate, due to lack of oxygen reaching the tissues
Treatment Options

If you observe any of the symptoms of onion poisoning, then it is imperative to rush the ailing dog to the veterinarian at once.

Blood tests and blood smear can help in confirming the poisoning, post which, appropriate treatment would be provided.

↬ Routine/Regular Treatment
Vomiting is induced, and gastric lavage (stomach is flushed out) is carried out, and activated charcoal (used for the treatment of poisoning and allergic reactions) is used to treat regular cases of onion poisoning.
In case of skin infection, the dog will be bathed and dried.

↬ Other Treatment
Fluids are provided in the bloodstream through the veins to maintain body hydration. There will be therapy for liver damage. In extremely severe cases, the vet might recommend blood transfusion as well.
Note: The anemia caused by onion poisoning is regenerative anemia, in which the body makes new blood cells. However, the entire process can take about a week. Meanwhile, the cell damage continues to happen.
To avoid the ill-effects of onions on your dog, it is important to monitor the food that your dog has. When you feed your dog anything, make it a habit to go through the ingredient list. This will save you and your dog from the hazards of such toxic foods.