Can Dogs Eat Onions? Why You Shouldn’t Feed Dogs Onions

onions in a woven basket
Fresh onion in basket on wooden table, top view

One of the most common questions that arises when considering food for dogs is, “Can dogs eat onions?” And the answer is no. Many people don’t know that onions are toxic to dogs. If you think about it, how many times have you made a meal for yourself and thought, “Oh, I will throw this onion in there! It’s good for me, so it must be good for my dog as well!” You’re not alone, but we are here to tell you that this isn’t true.

One of the most common foods that causes dogs to become ill is onions. Onions are toxic to dogs, and so are many other allium family members. This includes garlic, leeks, shallots, and chives.

This article will discuss why onions are bad for dogs, the symptoms of onion poisoning, treatments, and what to do to keep your dog safe in the future.

person hand feeding a dog

Can Dogs Eat Onions? Why Are They Bad For Dogs?

While onions are a popular ingredient in human food, they’re toxic to dogs. The same is true for onions of any variety: red, yellow, or white. It doesn’t matter if they’re raw, cooked, or in powdered form — the allium family can be dangerous for your dog. All parts of the onion plant are toxic to dogs, including the flesh and juice.

Onions contain sulfoxides and disulfides. When a dog ingests these chemicals, it can cause oxidative damage to the red blood cells in its body. There are two types of toxicities that result in dogs. The first is hemolytic anemia resulting from destruction of the oxygen-carrying red blood cells. The second is Heinz body anemia, which results from damage to the cell structure, causing them to be more easily destroyed by the spleen. While hemolytic anemia can be fatal, the good news is that this situation is treatable if caught early.

Specifically, a thiosulfate compound also damages a dog’s red blood cells. It can lead to hemolytic anemia, a severe medical issue that occurs when your dog’s red blood cells are destroyed faster than their body can replenish them. It’s not just onions that are dangerous for our furry friends.

Another reason that onions are bad for dogs is that they contain sulfur-based substances called organosulfoxides, which are toxic to dogs and other animals. These substances can destroy red blood cells in the body, leading to anemia and several health problems like vomiting, diarrhea, trouble breathing, and even death.

Onions are a member of the allium family which includes chives, garlic, and leeks. And like the rest of the allium family, onions can be very dangerous for dogs. Onions contain a toxin called thiosulphate, which repel pests and other animals. This toxin can damage your dog’s red blood cells if it ingests too much onion, resulting in hemolytic anemia — a severe medical condition.

Also, onions contain a compound called n-propyl disulfide, which is toxic to dogs. If a dog eats enough of it, its red blood cells will begin to break down, and the animal’s hemoglobin levels can become dangerously low. This condition is called hemolytic anemia, and it can be fatal.

All types of onions — red, yellow, or white — contain the toxic compounds that damage red blood cells in dogs. This includes dried onions like onion powder, raw and cooked onions, and even scallions, the green tops of scallions, and spring onions. Many vegetables are safe for your dog to eat, but experts recommend that you avoid feeding your pup raw vegetables or large amounts of vegetables. Some dogs might have trouble digesting these foods, causing uncomfortable gas or diarrhea. Onion poisoning can be fatal in dogs if left untreated.

puppy sitting behind an empty dog bowl

How Much Onion Can Make a Dog Sick?

When you’re cooking up a steak or roasting a chicken, it’s easy to forget that the ingredients you use to make your meal could be toxic to your dog. But some human foods can be dangerous for dogs, and onions are a big one.

The toxic dose of onion or garlic is much lower than the dose that could cause toxicity in cats. The reason for this is not apparent, but it may be due to differences in how dogs and cats process onions or garlic (such as how the body breaks down the onion or garlic).

It’s hard to say exactly how much garlic or onion is toxic for dogs because different species and breeds have different tolerances. The exact toxic dose is hard to determine since the strength of onions varies — shallots, for example, are more concentrated than white onions. Dehydrated onion products like onion soup mix or garlic powder are much more potent than fresh ones. But, on average, scientists consider a dose of 0.5% of a dog’s body weight to be toxic. So, if your dog weighs 50 pounds, around half an ounce of onion can be dangerous.

Since a large onion has about 44 grams of onion per ounce, one ounce of onion per 20 pounds of body weight is enough to send a dog into toxic shock. But even a smaller amount can be dangerous: an ounce of onion for every 10 pounds of body weight can cause visible damage to red blood cells.

Even a tiny amount of onion, garlic, or other toxic allium food can poison a dog easily. In addition, the smaller the dog, the greater the danger. Therefore, it is essential to know what types of human food your dog can safely eat as some foods are beneficial for dogs while other human foods can be dangerous for your dog’s health.

When you are dealing with onion poisoning, you must be aware of all the symptoms so that you can diagnose your dog with toxicity when you still have time to help. The last thing you want is to be left in the dark when your dog suffers.

puppy eating out of a dog bowl

What Are the Symptoms of Onion Toxicity?

Onion poisoning can happen if your dog eats a bowl of onion soup or gets into a bag of onion chips. However, even little amounts of onion powder can be dangerous to dogs. Since so many prepared foods contain onions, from hamburgers to pizza sauce, it’s essential to keep an eye on what your dog is eating — especially if you have children who may feed him table scraps.

Onion toxicity is dose dependent. There are no symptoms in cases of mild onion toxicity, and your dog will not need any medical treatment. For moderate to severe cases of onion toxicity, your veterinarian may prescribe a blood transfusion. In some cases, a particular diet may also be prescribed for two to three months after the transfusion to prevent further hemolysis.

Onions are toxic to dogs, cats, and other animals because they contain sulfoxides and disulfides. When mixed, the sulfoxide and sulfone in onions can damage red blood cells, causing them to break apart when they flow through the dog’s body. This leads to one of the most significant concerns of onion toxicity.

Hemolytic anemia (when the body destroys its red blood cells) is the most severe result of onion toxicity. When a dog ingests onions, the onion’s compounds cause the body to produce free radicals. Free radicals damage red blood cells in the body, leading to hemolytic anemia. In addition, when red blood cells are damaged, they become misshapen. These distorted cells are called Heinz bodies, and they can clump together inside your dog’s body, blocking his ability to absorb nutrients.

Also, under normal circumstances, the immune system generates antibodies against antigens on cell surfaces. However, when onion-damaged red blood cells are produced, the antibodies usually protect them instead of destroying them with their altered cell surfaces. This type of anemia is called immune-mediated hemolytic anemia (IMHA).

Not to mention, the damaged red blood cells can no longer carry oxygen throughout the dog’s body. A lack of oxygen-rich blood means that your dog’s organs won’t receive the oxygen they need to function correctly. This can cause severe damage to your dog’s organs and tissues, which could be fatal if left untreated.

Suppose you think your dog may have eaten onions. In that case, there are a few symptoms of anemia to look out for including weakness, decreased appetite, reddish urine, elevated heart rate, and panting as signs of onion toxicity.

Because onion poisoning in dogs can be fatal, it’s essential to know the symptoms of onion poisoning so you can get your dog to the veterinarian as quickly as possible if they show signs of illness after eating onions.

golden retriever eating out of a soup bowl

Can Dogs Eat Onions? Here’s What You Need To Know If They Do.

Onions are an everyday staple in many recipes. Whether you are using them raw in a salad, cooked in a stew, or sautéed as the base for your formula, onions add flavor and texture to all kinds of meals. Unfortunately, sometimes our pets decide to indulge in the same food that their owner is eating, even when we try to keep it away from them. So if your dog eats onions, you’ll want to know what to do next. So can dogs eat onions? Here’s everything you need to know if they do.

The best course of action for you to help your dog experiencing onion toxicity is to quickly take them to a veterinarian. The toxic effect of onions is cumulative; even if your dog appears to have recovered after an isolated incident of onion consumption, long-term effects on her red blood cells may be occurring that could cause problems down the road. The veterinarian will need more information about what type of onion your dog ate (white, red, or yellow), how much of the onion was eaten, and how much time passed before the signs appeared.

The poisoning results from the oxidation of iron in the hemoglobin of red blood cells resulting in their rupture and death. The ruptured erythrocytes accumulate in the spleen, liver, and bone marrow, where they interfere with the production of new red blood cells. Therefore, your veterinarian will likely want to run a complete blood count (CBC) and chemistry panel to evaluate the function of different organ systems and analyze your dog’s illness based on their symptoms. For example, suppose your vet detects the formation of Heinz bodies or hemolytic anemia in a blood sample, combined with a recent history of onion exposure. This will point your vet in the direction of treatment for onion poisoning.

If the poisoning is still recent, your vet may induce vomiting, and the dog may be given activated charcoal to reduce absorption of the toxins in the gastrointestinal tract. The veterinarian will tell you to monitor your dog for signs of anemia over the next few days and may recommend a diet low in oxidants. If a large amount has been ingested, your dog may need to be kept in a veterinary hospital for that period. Severely ill dogs will likely need supplemental oxygen to make up for the reduced circulation of red blood cells, and a blood transfusion could be necessary.

If you cannot reach your vet, contact the ASPCA Animal Poison Control Center at 888-426-4435 or Pet Poison Helpline at 855-764-7661.

The good news is that once your dog recovers from onion toxicity, it will not need lifelong treatment for this disease. However, if your dog has already been diagnosed with onion toxicity, you can help prevent future incidents.

dog holding an empty dog bowl in its mouth

Keeping Your Dog Safe From Onion Poisoning in the Future

If your dog has already been diagnosed with onion toxicity, you can help prevent future incidents by doing some detective work around your house. First, examine all foods, including table scraps and treats that you feed your dog, for ingredients that may contain onions (such as baby food). Also, look at any vitamins, supplements, or medications that your veterinarian may prescribe.

In the kitchen, keep all foods containing onions away from your dog. Take extra precautions when cooking with onions. Even a little bit can be toxic to dogs. For example, keep potholders off the floor and out of reach. Don’t mix up serving plates for family members and pets. And always wash your hands after handling onions to avoid accidental poisonings from touching pet food or pet treats after handling onions in the kitchen. If you keep onions around your house to cook with, keep them stored in a place that your dog can’t get into. And always clean up after cutting onions or garlic to ensure that no slices or pieces are left behind for your dog to eat when you aren’t looking.

In your garden, make sure that if you plant onions or any other plant in the allium family, you plant them away from where your dog can get them. For example, if you have a vegetable garden, grow it along your back fence line so that your dog stays out of it when they are out in the yard. If you have an onion bed close to the house, around a flower bed, or other garden area where your dog likes to spend time, put up some barrier (such as chicken wire) around the plants so your dog can’t reach them.

Onions are often included in different foods in tiny amounts (for example, a small amount of onion is sometimes included in pet food to enhance palatability). Still, those small amounts are enough to cause potentially serious problems for pets. Learn about the foods and products that contain onions and keep a list posted in your kitchen. You can also add “no onions” to your grocery list when shopping, so you don’t pick up pre-prepared foods with onion in them.

Since onion powder is used so often as a seasoning, it’s usually included in many things you may already have on hand at home. This includes dry soup mixes, processed meats, frozen dinners, and even potato chips. Even though trace amounts of onion powder may not appear to hurt your pet, remember that onions break down red blood cells in your dog.

Even though your dog can’t eat onions and garlic, other veggies are a healthy addition to your diet; they can also be a great addition to your dog’s diet. They can provide your pet with vitamins, minerals, and antioxidants. The key is to know which veggies are safe for dogs to eat and which aren’t.

If you want to give your dog vegetables as part of their regular diet, the best way is by mixing them in with their main meal. For example, you could give them some chopped carrots or green beans mixed with their kibble or wet food. You could also try giving them some chopped veggies as an occasional treat after meals.

Some of the most popular veggies include broccoli, carrots, and cucumbers. Broccoli can be a great source of vitamins K and C, fiber, and potassium for your dog in small amounts. However, large doses can cause stomach irritation and gas. Carrots are a healthy snack full of vitamins A, B6, C, K1, biotin, potassium, and fiber. They’re also deficient in calories, so they won’t make your dog gain weight even if you give them a lot. Finally, cucumbers contain vitamin K and a small amount of vitamin C, both very healthy vitamins for your dog.

Make sure that you understand what you are feeding your dog next time you reach for a treat and avoid all the foods in the allium family to avoid onion poisoning or onion toxicity.

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