Are Onions Toxic to Dogs


Onions are widely used in human food, but their impact on a dog’s health can be quite harmful. Onions🧅, along with garlic and other alliums, contain a substance called thiosulphate, which can be toxic to dogs🐕 when consumed in large amounts.

This toxin can damage the red blood cells in dogs and cause a condition called hemolytic anemia. In severe cases, it can even lead to death. So, the answer to the question, “Are onions toxic to dogs🐕” is yes.

What makes onions toxic to dogs

Are Onions Toxic to Dogs

Onions contain compounds called organosulfoxides, which break down into sulfur-containing compounds when ingested.

These compounds can cause oxidative damage to a dog’s red blood cells, leading to hemolytic anemia. The level of toxicity depends on the amount of onion ingested and the size of the dog. Larger dogs can tolerate small amounts of onion better than smaller dogs.

What are the symptoms of onion poisoning in dogs

The symptoms of onion poisoning in dogs can vary depending on the severity of the toxicity. Some of the common symptoms include:

  • Vomiting
  • Diarrhea
  • Loss of appetite
  • Abdominal pain
  • Lethargy
  • Weakness
  • Rapid breathing
  • Pale gums
  • Dark urine

In severe cases, a dog may experience collapse, seizures, or even death.

How much onion is toxic to dogs

The amount of onion that can cause toxicity in dogs depends on their size and weight. As a general rule, a dose of 0.5% of a dog’s body weight can cause onion poisoning.

For example, a small dog weighing 10 pounds would only need to consume 0.05 ounces of onion to become toxic. While a larger dog weighing 100 pounds would need to consume 0.5 ounces of onion to become toxic.

What should you do if your dog eats onions

If you suspect that your dog has eaten onions, you should take them to the vet immediately.

The vet may induce vomiting to remove the onion from their stomach or may administer medication to prevent the absorption of the toxin. In severe cases, your dog may require hospitalization and blood transfusions.

How to prevent onion toxicity in dogs

The best way to prevent onion toxicity in dogs is to avoid feeding them onions altogether. Be sure to check ingredient labels carefully, as onions can be found in a variety of human foods such as soups, sauces, and processed meats.

If you do feed your dog human food, make sure that it does not contain any onions or other alliums.


About 15–30 grammes per kilogramme of the dog’s weight, or roughly 5% of body weight, constitute the hazardous dosage. All species of Allium have the potential to produce this toxicity, but garlic is the most potent and, hence, the most harmful to canines.
Here’s the good news, so don’t completely panic: Although though they are hazardous to dogs, they may often consume tiny amounts of onion without experiencing any negative consequences. As a general guideline, dogs can safely eat up to 0.5% of their body weight in onions.

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