Can Dogs Eat Onions?

Onions are used in many dishes to enhance the flavor, and raw onions in salads are also not uncommon. Many people like to eat onions. But are onions also suitable for dogs?

Although onions are entirely safe for human consumption, they are highly toxic to dogs. You should, therefore, never give your dog onions in any form. Not only can onions cause vomiting and diarrhea, but they can also cause potentially fatal hemolytic anemia.

Onion poisoning is unpleasant for dogs as it can lead to various problems. Onions are highly irritating to the dog’s intestines and often lead to excessive drooling, vomiting, a sore stomach, and diarrhea.

However, these symptoms are only the more immediate, less dangerous problems. Onions can cause far worse problems.

So, if your dog has just eaten onions, you should see your vet immediately to get him checked out.

In this article, you will learn why onions are so dangerous for dogs, how much onion is toxic to dogs, and what you should do if your dog eats onions.

We also explain how onion poisoning in dogs can be treated.

Why Are Onions Poisonous to Dogs?

Onions contain a chemical called N-propyl disulfide, causing oxidative damage to red blood cells and destroying them. The technical term for this is hemolytic anemia.

The breakdown of these red blood cells results in not enough of them circulating in the body. This is known as anemia.

When there are not enough red blood cells, not enough oxygen is transported through the body, which leads to organ damage over time.

Anemia is challenging to detect and can be fatal, which is why onions are particularly dangerous and sneaky for dogs.

What Symptoms Do Dogs Experience After Eating Onions, and When?

Signs of stomach upset, such as loss of appetite, drooling, vomiting, and diarrhea, can occur within 30 minutes of eating the onion.

However, it can take several days for the more dangerous effects of potentially fatal hemolytic anemia to manifest fully. Symptoms of hemolytic anemia include:

  • Lethargy
  • Lack of movement
  • Pale gums
  • Weakness
  • Accelerated breathing
  • Increased heart rate
  • Red-to-brown-colored urine
  • Collapse

If your dog shows one or more of these symptoms, see a vet immediately.

How Much Onion Harm a Dog?

Even small amounts of onions can provoke symptoms of poisoning in dogs. Just 15-30 grams per kilogram of body weight can damage the red blood cells in dogs.

Scientific studies have shown that toxic effects occur when dogs eat onions weighing more than 0.5% of their own body weight.

The smaller the dog, the more susceptible it is to onion poisoning, as small dogs only need a tiny amount of onion for a toxic dose.

For example, a 30 kg German Shepherd would need to eat 150 g of onion to receive a potentially toxic dose. This is roughly equivalent to a small to medium-sized onion.

The consequences are far more dangerous for a 5 kg Jack Russell, who only needs to eat less than 25 g to get onion poisoning.

Research suggests that the toxic effects of onion consumption are cumulative.

So, if your dog eats small amounts of onions several times over a few days, there is still a risk of onion poisoning.

However, some dogs are affected even after eating fewer onions than the specified toxic doses. Other dogs can even eat more onions before it becomes toxic.

The dangerous amount depends on age, health, breed, and individual differences.

Breeds that are particularly susceptible to onion toxicity include Japanese breeds such as Japanese Chin, Akita, and Shiba Inu.

Are Cooked Onions Suitable for Dogs?

Onions belong to the allium family. All onion varieties, whether red, yellow, brown, green, or spring onions, are poisonous to dogs and cats.

The leek family also includes leeks, chives, garlic, and shallots. They are all equally dangerous if dogs eat them.

It is essential to know that all parts of the onion plant are toxic, including the leaves and sap. You should bear this in mind when growing onions in your garden.

The greatest danger to dogs is probably from raw onions that fall to the ground during cooking and are then picked up by a curious dog. However, boiled, baked, or fried onions are just as dangerous.

This is problematic as onions are very commonly used in many dishes, in ready meals, and in food from delivery services.

Onions are also often used as a flavoring agent in the form of onion powder, for example, in ready-made soups, frozen meals, and sauces.

It is probably not uncommon for dog owners to give their dogs food containing onions without knowing the risks.

Dogs can also snatch the onion during food preparation and during or after the meal. This can happen if the food is left unattended on the table or after the leftovers have ended up in the garbage can.

When dogs pick up onions from the trash can, there is also a risk that other high-risk foods or inedible items such as plastic or aluminum foil will also be consumed.

These other high-risk foods include grapes, cooked bones, fatty foods, and chocolate.

Many other vegetables, such as zucchini, pumpkin, and sweet potatoes, are safe for dogs.

What Should You Do if Dogs Have Eaten Onions?

If your dog has just eaten onions, you should take immediate action.

As mentioned above, you should contact your vet immediately. However, you should also take the following steps while you wait.

Look for the Symptoms

Is the dog behaving normally? Is it breathing faster than usual? Is there vomiting or diarrhea?

If your dog has pale gums, collapses, or gasps for air, treat this as an emergency and seek immediate veterinary attention. If your dog is wide awake and breathing normally, this is not necessary.

Prevent Further Access to Onions

Clean the floor of onions or onion-containing foods to ensure that other pets do not also access them and that your dog does not ingest more onions.

This also applies to the garbage can because an onion scent is highly tempting to dogs, especially when the onions are part of a tasty meal. It is best to use a garbage can with a lid that dogs cannot open.

Call Your Veterinarian

Because the toxic effects of onions can be so severe for dogs, you should seek veterinary advice as soon as possible.

Remember that small-breed dogs and puppies only need to ingest a tiny amount of onion to show signs of poisoning.

Give your vet all the relevant information over the phone. This includes, for example:

  • Your dog’s age, breed, health status, known illnesses, and size.
  • The amount of onion he may have eaten.
  • Any other foods he may have eaten.
  • When your dog ate the onion.
  • Any signs of illness or unusual behavior.

If your vet is concerned that your dog has ingested a dangerous amount of onions, they will ask you to come to the surgery.

If the vet’s surgery is nearby, it may be worth going straight to the vet rather than phoning first.

Try to Determine the Quantity

If you drop a raw onion on the floor and watch your dog eat it, it’s pretty easy to determine the amount.

Most of the time, however, onions are cooked and added to a dish. Try to remember how much onion was added to the dish and how much of it your dog may have eaten.

Check the labels of ready meals or ingredients for onions, onion powder, or related foods such as garlic.

If you think your dog may have eaten a dangerous amount of onions, or if you are unsure, you should call your veterinarian.

Watch Your Dog Closely

As soon as you get home from the vet with your dog, follow all the vet’s instructions closely. Watch your dog closely over the next few hours and days for any symptoms indicating onion poisoning.

Even if your vet thinks it is unlikely your dog had enough onions to get onion poisoning and advises you to wait and see, you should monitor your dog closely.

How is Onion Poisoning Treated?

Your vet will first take a thorough medical history and physically examine your dog.

If your dog has recently eaten onions and is otherwise healthy, the vet may induce vomiting to prevent the toxic effects such as hemolytic anemia.

Do not try to make your dog vomit at home unless your vet tells you to. Inducing vomit in dogs is not risk-free. This should only ever be done by a vet.

The vet will give your dog a drug to induce vomiting.

There are numerous home remedies to be found on the internet that can be used to induce vomiting in dogs. However, most home remedies are unsafe and may limit your vet’s subsequent treatment options.

The vet can also give your dog activated charcoal. Activated charcoal binds the toxins that are not excreted through the vomit so that they can pass through the intestines without being absorbed.

Conclusion: Can Dogs Eat Onions?

Under no circumstances should dogs eat onions, whether raw, cooked, or fried. Onions are poisonous to dogs and very dangerous.

If your dog has eaten onions, the first thing you should do is call your vet. You may need to visit the surgery for treatment.

Follow your vet’s advice to ensure your dog gets better.

Of course, the safest thing to do is to avoid eating onions in the first place. But with any luck, your dog will be fine once he has decided to eat an onion.