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For many people, the aroma of onions or garlic simmering in a pan is hard to resist. We also know how well they go in burgers, soups, pasta, and other common meals. The aroma is tempting for dogs, too, whose sense of smell is at least 10,000 times better than ours. Unfortunately, onions and other members of the allium genus are very toxic to dogs and cause life-threatening anemia. If your dog has ingested onions (particularly if it’s a large amount), urgent veterinary attention is warranted.
This article will explore onion toxicity in dogs while answering some questions you might have about why it’s so bad and what can be done about it.
Why Are Onions Bad for Dogs?
A very destructive component of onions (and similar species) causes red blood cells to burst. An organic sulfide molecule causes oxidative damage to red blood cells—think of this as the opposite of antioxidants. This results in anemia or a reduced number of red blood cells in the body. Red blood cells are vital for carrying oxygen around the body, so when dogs ingest too much onion and become anemic, different tissues in the body do not receive enough oxygen. This can be life-threatening.
It is not just onions that can cause anemia in dogs. Onions are part of a family of plants called the Allium genus, including leeks, chives, garlic, and shallots. All members of the Allium genus are toxic to dogs and capable of causing severe anemia.
What Are the Signs of Onion Toxicity?
Initially, onion ingestion may cause no signs of illness at all. Some dogs have gastrointestinal inflammation or “gut upset” on the first day following ingestion, resulting in vomiting, diarrhea, and sometimes abdominal pain.
Anemia following onion ingestion can take days to develop.
- Weakness and lethargy
- Reluctance to exercise
- Labored breathing
- Pale gums
- Dark/discolored urine
How Much Onion Is Toxic to Dogs?
In general. data suggests that as little as half a percent of a dog’s body weight in onions can cause toxicity. For example, a 20-pound dog would only need to eat 1.5 ounces of onion to suffer its toxic effects. The amount of onion required to cause toxicity in dogs seems variable.
While some dogs may tolerate a tiny amount of onion without any issues, others appear more sensitive to its effects. Cooked or rotten onions appear to be just as toxic as fresh onions. Additionally, some Japanese dog breeds, such as the Spitz, appear particularly vulnerable to the effects of onions due to unique genetic factors.
How Can Onion Toxicity Be Diagnosed?
Onion toxicity can be diagnosed using a combination of history-taking, physical examination, and several blood tests. These will include a total red blood cell count and an examination of red blood cells under the microscope to look for physical (“oxidative”) damage. Sometimes, imaging studies such as X-rays and ultrasound may be required to rule out other potential causes of anemia. There is no specific blood test to check for the presence of onion in a dog’s system.
How Is Onion Toxicity Treated?
This depends in part on how severe the signs of illness are. If only a tiny amount of onion was ingested, resulting in vomiting and diarrhea, but the risk of anemia is deemed low, management at home may be warranted. This may involve activated charcoal, anti-nausea medications, and probiotics.
Dogs experiencing anemia due to onion ingestion require more intensive and aggressive treatment. This may include fluids via a drip to correct dehydration, blood transfusions, oxygen supplementation, supportive medications (as above), and monitoring at a vet hospital.
My Dog Just Ate Onions – What Should I Do?
If your dog eats onions, or if you’ve fed them to your dog unaware of their potential harm, visit your veterinarian. Vets will often give dogs medication to make them vomit, which should rid the stomach of onions and prevent the risk of anemia developing in a few days. If your dog ate onions a few days ago and is now showing signs of being unwell, you should also arrange an urgent visit to your veterinarian, as diagnostics and treatment may be required.
Conclusion
Dogs are very susceptible to onion poisoning, and the anemia caused by onions can be life-threatening. Thankfully, vets can induce vomiting early to get rid of the onions from the stomach; treatment for anemia is also possible and usually gets dogs back into good health. As always, early veterinary intervention gives your canine companion the best chance of a positive outcome.
In the meantime, keep any onion-based meals away from your dog, and if they like vegetables, consider cucumber or carrots instead.
Featured Image Credit: Shutterbug75, Pixabay
