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 the 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.


In the end, onions are harmful to dogs and must be avoided from their food and in their environment.

Onions are a source of compounds known as thiosulfates which may cause harm to dogs’ red blood cells and lead to a serious illness that is known as hemolytic Anemia.

Even a small amount of onions could be dangerous as both raw and cooked onions can pose a threat to dogs.

If you suspect that your pet has eaten onions or is showing any signs of poisoning caused by onion symptoms, including vomiting, weakness, or breathing problems it is crucial to seek immediate veterinary care.

Are Onions Toxic to Dogs – FAQs

Are onions toxic to dogs?

Yes, onions are toxic to dogs. They contain compounds that can cause health issues when ingested.

What makes onions toxic to dogs?

Onions contain thiosulfates, which can damage a dog’s red blood cells and lead to a condition called hemolytic anemia.

Can a small amount of onions harm my dog?

Even a small amount of onions can be harmful to dogs, especially if consumed regularly or in concentrated forms.

What are the symptoms of onion poisoning in dogs?

Symptoms may include weakness, lethargy, pale gums, vomiting, diarrhea, increased heart rate, and difficulty breathing.

How soon do symptoms appear after a dog ingests onions?

Symptoms can occur within a few days after onion ingestion, depending on the amount consumed.

Can cooking onions be safe for dogs?

No, cooking does not eliminate the toxic compounds in onions. Both raw and cooked onions can be harmful.

Are all types of onions equally toxic to dogs?

Yes, all types of onions, including red, white, yellow, and even onion powder, contain thiosulfates and are toxic.

Can onions be part of a dog’s diet in small quantities?

It is not recommended to include onions in a dog’s diet, even in small amounts, due to their potential toxicity.

Can onion poisoning be fatal for dogs?

Yes, severe cases of onion poisoning can lead to life-threatening complications and, in some instances, death.

Are some dog breeds more susceptible to onion toxicity?

All dog breeds can be affected by onion toxicity, but certain breeds may be more sensitive to it.

What should I do if I suspect my dog ate onions?

Contact your veterinarian immediately, providing details about the amount and time of onion ingestion.

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