My Dog Ate Onions! Here’s What to Do (Vet Answer)

My dog ate some onion

Onions sometimes make us cry, but did you know that onions can be life-threatening to dogs and cats?1 In fact, all members of the onion family (“Alliums”—garlic, onion, chives, and leeks) and their products (such as onion powder for example) can pose a danger, but onions are the most poisonous. Dogs are among the most vulnerable to onions in the animal kingdom, and humans are among the least, due to differences in their metabolism. In this article, we will explore why and how to deal with the problem.My dog ate some onion

Why Can’t Dogs Eat Onions?

Onions and alliums contain organosulfur compounds that affect cell processes in the body by causing oxidative damage—the opposite of those familiar ‘antioxidant’ products. Dogs and cats are extremely sensitive to these compounds. Most of the damage is to red blood cells, which can lead them to work less efficiently, or even die. These changes produce tell-tale changes in the appearance of the red blood cells, which can be seen under a microscope (more on that later).

The knock-on effects of this red blood cell damage can affect the liver and kidneys, too. Other compounds in onions can also affect the lining of the intestines, which may cause pain and diarrhea.

How Much Onion Can Kill a Dog?

No two dogs are the same so this toxic amount can be very variable and individual. A good rule of thumb to work with for dogs is approximately 5 grams of onion per kilogram body weight—or just under 1 ounce of onion per 10 pounds body weight. Some dogs may be a bit more resistant than those numbers might suggest, but it is safer to assume that any amount of onion is potentially a risk.

Generally, if a dog eats more than half a percent of their body weight in onion, they will develop toxicity if left untreated. In real terms, if a 66-pound (30 kg) Labrador ate 5 ounces (150 g) of onion or onion product—which is only the weight of one medium onion—he or she would be at risk of poisoning.

Remember that any part of the onion plant can be toxic, and it is still toxic if cooked (think onion rings, for example). The effects can also accumulate if a dog is fed smaller amounts of onion over a few days. Watch out for onion powder, as this is commonly added to lots of processed foods.

My dog ate some onion
Image Credit: Igor Normann, Shutterstock

My dog ate some onion

What to Do if Your Dog Eats Onions

1. Prevent further access.

Prevent your dog from eating any further onion or onion products. It is important to limit the amount eaten as much as possible. Clean up any spills on the floor or accessible products on surfaces and shut your dog away while you do this. If your dog has had processed food with onion in it, it is worth making sure there are no other sources in any other foods.

2. Get the details.

Work out how much onion your dog has eaten and take note of when it happened.  It is important to try and work out roughly how much onion product your pet has eaten, so the veterinarian can use this with the body weight of your pet to calculate whether this is likely to be a toxic dose or not. It is also useful to try and figure out when the onion was eaten, as this will help the veterinarian plan the right treatment for your dog.

3. Call your veterinarian.

In all cases, it is essential to seek the advice of your veterinarian, even if it’s just a phone call to discuss the situation! Provide the veterinarian with the information you have gathered—they will be able to help formulate a plan of action. If your usual veterinarian is not available, an emergency clinic or the nearest open veterinarian will be able to provide you with the correct advice.

4. Follow your veterinarian’s instructions.

The veterinarian may recommend seeing and examining your dog at the clinic, and the sooner this happens the better your chances of a successful outcome. If the amount eaten is not a toxic dose, the veterinarian may be happy for you to monitor your dog at home, but it is best to seek advice first in any case.

5. Don’t treat at home.

It is important not to try and treat these problems at home. It is easy to cause more harm than good with a home remedy- many are unproven or even dangerous. Any delay in using inappropriate or ineffective remedies may mean that a treatable problem is left too long, and it may be too late if you later decide to seek professional help.

Related Read: My Dog Ate Raw Chicken! – Here’s What to Do (Our Vet Answers)

My dog ate some onion
Image Credit: Veronika 7833, Shutterstock

My dog ate some onion

What Happens if a Dog Eats Onions?

How long after eating onion will a dog get sick?

Usually, symptoms will appear within 1 to 3 days of the onion being eaten. It often starts as a tummy upset, with vomiting, diarrhea, tummy pain, lethargy, and loss of appetite. This is then followed by the effects of the red blood cells being damaged and dying.

Having low numbers of red blood cells is a condition called anemia, and this will turn the normally bright pink gums above their teeth pale, and cause weakness. Their bloodstream will no longer carry oxygen around the body effectively, so dogs may breathe extremely fast to compensate, or seem to struggle to breathe. Additionally, their heart rate will be high. They may also produce dark brown or red urine, caused by the body removing all those damaged or dead red blood cells.

Anemia and dying red blood cells can damage the liver and kidneys and unfortunately, in some cases dogs and cats will die due to these effects. But don’t panic yet—this onion poisoning can be treated as long as you seek help in time!

Can onion poisoning in dogs be treated?

If you realize that your dog or cat has eaten onions or their products within the past 4 hours, your veterinarian can usually give an injection to cause vomiting to bring up most of the toxins before they have a chance to be absorbed into the body. Sometimes a product to protect the gut from any leftover toxins is prescribed afterward—activated charcoal for example. In these situations, the outcome is usually excellent.

If more than 4 hours have passed, it is best to start supportive therapy as most of those toxins are likely to have been absorbed. You and your vet should look for the symptoms listed above. The veterinarian can also perform a blood test to check for any red blood cell damage and look for any changes to the liver and kidneys that can follow that damage. Under the microscope, the veterinarian may be able to see evidence of damaged red blood cells, appearing as little blobs called Heinz bodies on the outside of each cell.

Can onions kill dogs?

If onion toxicity is suspected or confirmed, quick action and early treatment are a good idea. Treatment consists of hospitalization and intravenous fluids to dilute the effects of the toxins and ensure the body stays well hydrated. There is no specific antidote, but pain relief, anti-nausea drugs, and appetite stimulants all may help.

Read more  Poisoned Pets | Pet Food Safety News

Supportive care helps your pet’s body keep going while it flushes out those toxins and replaces the damaged red blood cells. In severe cases, if too many red cells are lost, a blood transfusion and extra oxygen for breathing may be needed, but this is not common. Whilst dogs can die from onion poisoning, it’s very rare as long as they get treatment.

My dog ate some onion
Image Credit: Ruth Black, Shutterstock

My dog ate some onion

Conclusion: Dogs and Onions

Dogs and cats are extremely vulnerable to onion poisoning and the effects can be life-threatening. However, it can be treated and managed as long as you act quickly to identify the problem and seek professional veterinary help as soon as possible. In the majority of cases, your pet is likely to make a good recovery. And don’t worry, there are lots of other perfectly safe and healthy vegetables to add to your dog’s diet, including carrots, cucumbers, and broccoli

  • See also: Can Dogs Eat Scallions? Is It Healthy or Unsafe?

Featured image credit: Liliya Kulianionak, Shutterstock

— Update: 09-02-2023 — found an additional article What Should I Do if My Dog Ate a Small Piece of Onion? from the website for the keyword my dog ate some onion.

Most dog owners know that chocolate is toxic. But if you gave your dog a meal with onion or you caught them using an onion as a chew toy, it might get you wondering—my dog ate a piece of onion; what should I do?

Onions are toxic to dogs, but the toxicity level depends on the dog’s size and how much they eat.

My dog ate some onion
What should I do if my dog ate a small piece of onion?

So, I’ll help you understand how to determine if your dog needs to see a vet after consuming onion and what toxicity symptoms to watch out for.

Determining if Your Dog Ate a Toxic Amount of Onion

Before you go into full-out panic mode, here’s the good news: Although onion is toxic to dogs, they can usually eat it in small amounts without harmful side effects.

The general rule of thumb is that it’s safe for dogs to consume up to 0.5% of their body weight in onions. 

Yes, I understand that it takes some calculating. So let me help you out.

If you own a six-pound Chihuahua, they can eat as much as 0.03 pounds of onion before they could experience life-threatening issues. In contrast, an 80-pound Labrador Retriever can consume as much as 0.4 pounds of onion with little chance of having harmful side effects.

The bottom line?

The amount of onion and your dog’s body weight combined makes the difference in whether they’ll have adverse side effects.

My dog ate some onion
Pomeranian is anxious looking on the floor.

Why Onions Are Toxic to Dogs?

The reason that onions are toxic to dogs is that they contain n-propyl disulfide

I won’t get too scientific on you, but N-propyl disulfide breaks down red blood cells, which can result in anemia. Anemia is dangerous because it causes arrhythmia (irregular heartbeat) and an increased heart rate.

As a result, your dog’s heart has to work faster to pump blood throughout its body, leading to an enlarged heart, heart failure, and, in worst-case scenarios, death. 

Although some people can experience allergic reactions or issues with drug interactions when consuming onions, onions generally don’t have the toxic effect on humans as they do on dogs.

My dog ate some onion
Is onion bad for dogs?

The Allium Species Conundrum

Onions are part of the allium species, which is a group of plants that can create toxic reactions to dogs. So, aside from eating onion, your dog could have an increased chance of toxicity if the onion-filled dish also contained allium species such as:

  • Garlic
  • Chives
  • Leeks

Luckily, most dogs won’t naturally want to gobble up these foods. That’s why toxicity from onion and other allium species more commonly occurs from them eating a dish containing one or more of these ingredients. 

If it’s any consolation, garlic is the most toxic of all the allium species; it’s about five times more toxic than onion.

My dog ate some onion
Garlic and chives are both toxic for dogs.

The Two Types of Onion Toxicity

As you’re contemplating, “My dog ate a piece of onion. What should I do?” there’s another layer to consider.

As if it couldn’t get worse for the worried dog owner, your dog may undergo one of two types of onion toxicity:

  1. Instant onion poisoning.
  2. Delayed onion poisoning.

Instant onion poisoning is the most common, as it occurs when your dog consumes significantly more than 0.5% of its body weight in onion.

You’ll notice symptoms of onion toxicity shortly after your dog eats onion if they’re going to have an “instant” reaction, although it could take as long as 72 hours.

The second type of onion toxicity is when N-propyl disulfide gradually builds up in your dog’s system by eating onions over several days. The toxin will then build up in their system, rearing its ugly head as it starts impacting your dog’s red blood cells.

Some dog owners may unknowingly be giving their dog a toxic amount of onions if they’re sharing leftover onion-containing food with their dog multiple days in a row.

For this reason, among many others, it’s best to stick with feeding your dog their canine-appropriate dog food.

My dog ate some onion
Chihuahua is not feeling well inside the car. Heading to the vet clinic!

Does It Matter if the Onion Is Cooked or Raw?

Dogs can react equally to onions, whether they’re cooked or raw.

Therefore, even though it’s gross (and seemingly unlikely unless they have pica), your dog can have onion toxicity by chowing down on raw onions and grabbing some fried onion rings off your kitchen counter. 

So, the rule of thumb is to always keep onions out of your dog’s reach regardless of what cooked state the onions may be in.

My dog ate some onion
A chocolate Toy Poodle eating from a ceramic bowl

What About Powdered Onion?

Powdered onion is toxic for dogs, too, since it contains N-propyl disulfide. 

In fact, powered onion can be even more toxic since it’s so concentrated and easier for a dog to consume in greater amounts.

My dog ate some onion
Onion powder is harmful to your dog’s health.

Watching for Signs of Onion Toxicity

If you feel your dog ate more than 0.5% of their body weight in onion, I encourage you to take them to the vet immediately. 

Otherwise, it’s still important to monitor your dog in the hours after they consume onion. Some signs that your dog is experiencing onion poisoning include:

  • Vomiting
  • Diarrhea
  • Lethargy
  • Collapse
  • Excessive panting
  • Irritation in the mouth
  • Stomach that’s sensitive to the touch

In more progressive cases of onion toxicity, your dog might develop pale gums, and their heart will start to race. At that point, taking your dog to the vet as quickly as possible is critical, as this is a dangerous and life-threatening state.

My dog ate some onion
Dachshund lying on the clean floor.

How a Veterinarian Treats Onion Toxicity?

A veterinarian will take different approaches to treat onion toxicity depending on your dog’s symptoms and how much time has passed since they consumed the onion.

If you drove your dog to the vet as soon as you caught them eating onion, then your veterinarian will likely induce vomiting to help the onion get out of their system before the N-propyl disulfide has time to attack their red blood cells. 

Alternatively, they may use a tube to administer activated charcoal. Activated charcoal can be effective at removing toxins, as it’ll absorb them from your dog’s blood.

If your dog has a severe bout of onion toxicity, they’ll likely also put your dog on oxygen. That’s because, with a lack of red blood cells, your dog will experience reduced circulation, which is dangerous for their health.

In worst-case scenarios, your veterinarian might even perform a blood transfusion. Doing so will help stabilize your dog and allow its bone marrow to generate red blood cells, which will allow them to leave the vet with a new lease on life.

You can also expect your veterinarian to run blood tests, checking for your dog’s red blood cell status and oxygen levels.

My dog ate some onion
Pug getting a check-up in a veterinary clinic.

How To Prevent Your Dog From Eating Onions?

Although most dogs won’t want to eat onions raw, they could see raw onions as a play toy. And, of course, it can be hard to hide the scent of cooked onions, especially if you’re giving them cooked onions with meat.

So, some of the best ways to prevent your dog from eating onions include:

  • Keep raw onions out of reach of your dog.
  • Never feed them foods with onion or onion powder.
  • Don’t leave onion-filled food on the counter.

Of course, if your dog is grabbing food off your counter, you have an entirely separate issue on your hands. There’s nothing that some good, consistent training can’t take care of, though.

If you want to feed your dog raw onions for whatever reason, you can give them several safe fruits and vegetables instead. Carrots, apples, celery, bananas, beets, and cucumber are some of the many dog-friendly foods.

Read more  Dog Cherry Eye Surgery Costs and Procedure

Contrary to popular belief, dogs are omnivores. That’s why dog food often contains vegetable ingredients. So, you’re welcome to add veggies to your dog’s diet as long as they’re not in the form of onions and certain other toxic plants.

My dog ate some onion
Samoyed dogs in the kitchen, waiting for their food.

The Bottom Line

It isn’t always common knowledge that onions are toxic to dogs. So if you came here searching “My dog ate a piece of onion,” I applaud you for being proactive in figuring out what to do.

Not all dogs that eat onions need to go to the vet. If they consume 0.5% of their body weight or less in onions, their bodies will likely be able to manage the onion without treatment.

Nevertheless, I know it can be hard to determine the weight of how much onion your dog ate. Plus, like any good dog owner, you’re understandably worried about your pooch. So, when in doubt, it’s always wise to take your dog to the vet for peace of mind.

— Update: 09-02-2023 — found an additional article Can Dogs Eat Onions? How much is toxic to dogs? from the website for the keyword my dog ate some onion.

This post will give you everything you need to know about the complex and toxic relationship between onions and dogs, including what makes onions a major no-no for canines, what will happen to your dog if he happens to ingest an onion, and what action you should take should such an instance occur. In most cases, it’s important to take your dog to the vet as soon as possible.

Is It Bad If My Dog Ate Onions?

Dogs can actually get sick from both raw and cooked onions.  And the harm an onion can cause a canine goes well beyond bad breath — it can even be life-threatening.

The agent in onions that is toxic to dogs is known as N-propyl disulfide or thiosulfate. This is a compound that causes a breakdown of red blood cells because dogs do not have the enzyme needed to digest this substance. This can lead to anemia in dogs, among other potential canine health problems.

More specifically, the toxic portion of an onion can cause damage to your dog’s red blood cells by attaching to the oxygen-transporting protein, called hemoglobin, in your dog’s red blood cells. This will reduce the red blood cells’ ability to carry oxygen throughout the animal, and will also trick your dog’s body into thinking that the blood cell is an invader. This triggers a process known as hemolysis, which will destroy the red blood cell and result in hemolytic anemia.

When hemoglobin is oxidized, it will form clumps called Heinz bodies. These Heinz bodies cannot carry oxygen, and will cause the red blood cells to carry oxygen less efficiently.

What Part of an Onion is Toxic to Dogs?

No specific part of an onion carries the toxin that is harmful to dogs — they’re in the whole thing! Onion Toxicosis can occur from ingestion of:

  • Onion flesh
  • Onion juice
  • Onion leaves
  • Processed onion powder

This means that onions can cause harm to dogs if they are consumed even after they are cooked, fried, or powdered.

My dog ate some onion

Onion powder is also in a surprisingly wide range of human foods, and it doesn’t take a lot of onion to get a dog sick. For example, a 45-pound dog would only need to eat one medium raw onion to experience dangerous levels of toxicity. It’s difficult to keep a watchful eye on a dog at all times when food is out, but it is especially important if onions are involved.

Similar Foods That Can Also Be Harmful

Actually, all other foods in the allium family are also harmful, including:

  • Garlic
  • Scallions 
  • Shallots 
  • Leeks
  • Chives

These foods are also harmful to dogs as they contain the same toxin. Be extra cautious if your dogs eat Onion and garlic powders; they are actually even more potent than fresh onions, which is dangerous news because they are found in so many human foods. Always check the labels of any foods you give your dog to make sure no onion or garlic powders are included.

How Much Onion Does it Take to Make a Dog Sick?

There are many factors that determine how much onion it will take to cause problems in your dog, including the amount ingested, the dog’s size, and other biological factors. Generally, if your dog eats a small number of onions, he will probably be fine. However, if he frequently consumes onions it can lead to dog health issues.

If the dog consumes a large number of onions at one time, your canine may suddenly develop anemia for the following days. Consumption of small amounts over a duration of time can cause a gradual development of anemia.

The onions consumed also do not have to be raw to cause harm. They can be dehydrated in soups, fried in onion rings, or prepared in any other way. Much like garlic powder, onion powder in baby food has been known to cause a rash of onion poisoning, as small children often let dogs eat their food or leave it lying around for their dog to find.

Symptoms of Onion Toxicity in Dogs

Symptoms you should look out for include:

  • General canine weakness
  • Red urine
  • Decreased appetite
  • Decreased stamina
  • Pale or bluish gums (especially with exercise)
  • Fainting
  • Vomiting
  • Elevated heart rate

Onion toxicity is not a common cause of the last three symptoms but could be the culprit if you know or suspect your dog has gotten into some onions recently.

Onion ingestion in dogs can also lead to:

  • Liver damage
  • Canine asthma attacks
  • Allergic reactions
  • Diarrhea
  • Anemia
  • Dermatitis
  • Overall weakness

Many of the signs and symptoms listed above are actually caused by Heinz Body Anemia, or Hemolytic anemia. This is a condition that is brought on by the destruction of the dog’s red blood cells, which leads to a decrease in his red blood cell count, causing anemia.

The symptoms a dog experiences will depend on the number of onions it has consumed, its size, and the time period in which the onions were ingested. Consuming a large quantity of onions in a single sitting is actually less dangerous than eating a small number over a long period of time. This is important to remember if you are someone who likes to feed your dog from the table, as many foods people eat contain at least a small number of onion powder in them. Make sure you read your food labels carefully so you aren’t unintentionally poisoning your dog.

It’s also important to note that symptoms typically won’t appear for a few days after the dog has consumed the onions, and it may be safe to monitor your pet, however, if a large number of onions are mysteriously missing, you should bring your dog in to see your veterinarian just in case.

Likewise, if you know for sure that your dog has consumed a large amount of onions, it’s best to take your dog to your veterinarian immediately. Your vet will diagnose your dog’s condition based on his symptoms and blood work and may induce vomiting or give your dog a solution that will help decrease the absorption of the onions in the blood. Getting your dog into the vet quickly may help spare you some costly medical bills that are associated with overnight stays and monitoring should your dog’s onion toxicity reach dangerous levels.

How is Onion Poisoning Diagnosed?

It’s certainly easiest for your veterinarian to make a diagnosis if you know that your dog has ingested onions or a product that contains onions. If your dog is already showcasing symptoms like lethargy and weakness, then a low red blood cell count will likely be visible on a blood test. This can help indicate how severe the problem is as well.

Hemoglobin forms clumps on your dog’s red blood cells, which makes them not carry oxygen as well. When your veterinarian views your dog’s blood sample under a microscope, a dog with onion toxicity will showcase the telltale sign of these little clumps, which appear purple on the red blood cells. Other health conditions can cause these symptoms, but if it is suspected that the dog consumed onions, this will often be enough for a diagnosis.

Other times, your veterinarian will also conduct a urinalysis to see if there are high levels of hemoglobin in the urine. Heinz body anemia may also be visible in a blood smear examination even before the condition has caused a drop in the dog’s red blood cell count.

Other times, you may have to check your dog’s stool for undigested pieces of onion or analyze his vomit if he has become nauseous. Your veterinarian may also ask you what foods you regularly give your dog, and have you check the labels for a list of ingredients.

Read more  Toad Poisoning in Dogs: Everything Pet Parents Should Know

What to do if your Dog Eats Onions

My dog ate some onion

If you see your dog eating onions or suspect that your dog has eaten them, your best course of action is to seek immediate veterinary care, especially if your dog seems like he isn’t feeling well or is tired and weak. Your vet will evaluate your dog and take the proper course of action.

Once at your vet, treatment will depend on when your dog consumed the onions. If it was just before you brought your dog into the vet, your veterinarian will usually induce vomiting to flush out your dog’s stomach. They may also use activated charcoal to treat the poisoning as well as potential allergic reactions.

Activated charcoal reduces absorption of the onions in the gastrointestinal tract. After this initial course of treatment, your vet may also bathe and dry your dog to prevent the risk of skin infection. You may also need to monitor your dog for a set time period and make sure your dog stays hydrated.

In cases where the dog is more seriously ill and anemia has set in, the veterinarian will give the dog fluid into his bloodstream, treat any present liver damage, and call for blood transfusions if necessary. Some dogs may require supplemental oxygen to make up for the reduced circulation of red blood cells in their body. Sometimes this will require your dog to be kept overnight or longer.

Once you are able to take your dog home, your veterinarian will tell you how to monitor your dog, outlining specific signs of anemia for you to look for over the coming days.

Since onion toxicity can be fatal in severe cases, it is best to get your dog to the veterinarian as soon as you suspect something is wrong.

Healthy Vegetables for Dogs

While onions and other vegetables in the allium family can be toxic to dogs, there are many other safe human food options your dog is sure to love. Kale, spinach, broccoli, carrots, beets, and sweet potatoes are all great examples you can supplement with traditional dog food to help keep your dog healthy for years to come.

Long-term Outlook for Dogs with Onion Poisoning

While severe poisoning can be fatal, especially if left without treatment, dogs with mild cases of onion toxicity will make a full recovery in short order. You will simply need to continue to monitor your dog for symptoms and make sure he is unable to ingest any more onions.  


  1. Burke, Anna. “Can Dogs Eat Onions?” American Kennel Club, 2017. Accessed 12 Sept. 2019.
  2. Lowrey, Sassafrass. “Can Dogs Eat Onions? If Your Dog Ate Onions, What Do You Do?” Dogster, 2018. Accessed 12 Sept. 2019.
  3. Yin, Sophia. “Onions and Dogs, A Lethal Combination.” Cattledog Publishing, 2009. Accessed 12 Sept. 2019.

Canna-Pet aims to provide accurate and up-to-date information to help our readers make informed decisions regarding their pet health. This article was written based upon trusted scientific research studies and/or articles and was written and reviewed by certified professionals. Credible information sources for this article are cited and hyperlinked.

— Update: 10-02-2023 — found an additional article Can Dogs Eat Onions? Here’s What You Need To Know from the website for the keyword my dog ate some onion.

Onions are unique members of the root vegetable family because they (like garlic) are bulbs and do not grow as deeply as other root vegetables. Onions come in white, yellow, and red bulbs, as well as chives and leeks, and are a common flavorful addition to meals and side dishes, served both cooked and raw. They help bring flavor to many of our favorite dishes, but can dogs eat onions? If your dog ate onions, what do you do?

First, what to know about dogs and onions

We spoke with Emmy-award winning veterinarian Dr. Jeff Werber to learn more about how dangerous onions are for our dogs. Dr. Jeff explains, “Traditionally, we have always recommended avoiding raw onions and raw garlic because of a type of toxin that can have a negative effect on red blood cells.” The toxic ingredient is called n-propyl disulfide, which is an oxidant that can do oxidant damage to red blood cells.

Can dogs eat onions?

Well, you shouldn’t give your dog a bowl of onions to snack on. Onions aren’t healthy for dogs, but unlike grapes, where even a small amount can be toxic, onion toxicity depends on how much of an onion a dog consumes. Embrace Pet Insurance Claims Manager Rachel Hinder RVT explains that “Typically if a dog ingests only a small amount of onion, it should not cause any problems.” However, she did caution that “the size of the dog also matters, small pieces of onions are a lot bigger problem for tiny 3-pound Yorkies than 200-pound Great Danes.”

One of the dangers of onions and dogs is that the toxins can build up in their system, meaning that they could slowly be reaching a point where an onion exposure could get them sick, or that there might be what Dr. Werber calls a cumulative effect. “To be safe, avoid onions and garlic,” Dr. Werber suggests. Consuming onions can lead to dogs developing a condition called hemolytic anemia. This condition impacts/destroys a dog’s red blood cells, leaving dogs without enough of them for healthy functioning. Severe onion poisoning in dogs can be fatal.

Can dogs eat cooked onions?

Although onions might not be as toxic to our dogs as grapes or xylitol, avoid giving onions to your dog regardless of if they are raw or cooked. Cooking onions doesn’t have an impact on the safety of onions and cooked onions are still poisonous to dogs because of their toxic effect on a dog’s red blood cells. All forms of onion can be toxic to dogs — whether powdered, dried, fresh or cooked.

Can dogs have broth cooked with onions?

If you are cooking for your dog or treating your dog to some snacks from your plate, avoid sharing any food with your dog that has been cooked with onions including if you use onions in your broth. Hinder advises that “although a small amount of onion is unlikely to cause problems, it is safer to avoid all together.”

Similarly, if you are purchasing a pre-made broth, read the labels on the broth and select a broth that doesn’t include onions. Hinder encourages dog guardians to also look for onion powder as an ingredient in pre-made foods and avoid using in any recipes you will be sharing with your dog because it is made up of dried and ground onions and can be harmful to your dog.

No matter if you are using the onion’s juice, flesh or even leaves, all parts of the onions will cause issues with dogs. Do not cook something with onions for your dog or even onion powder.

What to do if your dog eats onions

To be safe, keep all onions and all products containing onions away from your dogs. But what happens if you’re cooking and you drop a slice of onion on the floor or a friend shares a bite of their lunch with your dog and it includes onion? While we don’t want our dogs eating onions, having a bite of something with onion isn’t likely to make your dog sick. “Your dog probably would not eat enough to cause a real problem because dogs typically don’t like the taste,” Dr. Werber says.

If you think your dog ate onions in large quantities, or if your dog seems like he isn’t feeling well, Dr. Werber suggests seeking immediate veterinary care. Your veterinarian will be able to evaluate your dog and determine if any treatment is necessary.

Symptoms of onion toxicity are symptoms of anemia — when your dog has low red blood cells. Look for decreased appetite, weakness, lethargy and pale gums. The ASPCA’s animal poison control site ( also says that clinical signs include vomiting, panting and high heart rate. If you see any of these symptoms, take your dog immediately to the veterinarian.

Thumbnail: Photography © vvuls | iStock / Getty Images Plus. 

This piece was originally published on May 4, 2018.

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