Fresh picked onions

Can Dogs Eat Onions? No, Onions Are Toxic to Dogs. Onions, along with all members of the Allium family, are toxic to dogs and can lead to potentially fatal health issues.

Understanding Onion Toxicity in Dogs

Onions contain thiosulfate, a compound that dogs cannot properly digest. Even in small amounts, onions can be harmful to dogs, leading to a condition called hemolytic anemia.

This condition occurs when red blood cells are destroyed faster than they can be produced.

Symptoms of Onion Poisoning in Dogs

The consumption of onions can cause a variety of symptoms in dogs, which may appear within a few days after ingestion:

  • Lethargy or Weakness: Dogs might seem unusually tired or weak.
  • Reduced Appetite: Affected dogs may lose interest in food.
  • Pale Gums: As a sign of anemia, the gums may appear paler than usual.
  • Red or Brown Urine: The presence of hemoglobin in the urine due to the breakdown of red blood cells can change urine color.
  • Vomiting and Diarrhea: These are common signs of gastrointestinal distress related to onion poisoning.

Types of Onions and Related Foods to Avoid

A selection of root vegetables, including onions, shallots and garlic.

All forms and varieties of onions are harmful to dogs, including:

  • White Onions: Often found in raw dishes, they contain the same levels of thiosulfates as other onion colors.
  • Red Onions: Used in many cuisines around the world, they are slightly higher in antioxidants but have similar thiosulfate levels.
  • Yellow Onions: A staple in cooking due to their rich flavor, they contain comparable amounts of toxic compounds as their white and red counterparts.
  • Shallots: These are smaller than typical onions but are dense in thiosulfate and other compounds harmful to dogs.
  • Green Onions (Scallions): While they might appear less formidable due to their size and milder flavor, green onions still contain thiosulfate, making them just as dangerous.
  • Garlic: This is considered more dangerous to dogs on a weight-for-weight basis than onions. Even a small amount of garlic can lead to toxicity symptoms.
  • Chives: Similar to garlic, chives are potent and dangerous, even in small amounts. They contain the same types of organosulfur compounds found in garlic, contributing to their toxicity.
  • Cooked, Raw, or Dehydrated Onions: The form of onion does not affect its toxicity.

Immediate Steps if Your Dog Ingests Onions

If you suspect that your dog has eaten onions, immediate action is crucial:

  • Contact Your Veterinarian: Quick veterinary attention is essential to manage onion poisoning effectively.
  • Induce Vomiting: Only under the guidance of a veterinarian, inducing vomiting can help if the ingestion was very recent.
  • Activated Charcoal: Your vet might administer activated charcoal to help absorb the toxins.
  • Supportive Care: Depending on the severity, supportive care, including IV fluids and blood transfusions, may be necessary.

Preventing Onion Poisoning

Prevention is key when it comes to keeping your dog safe from onions:

  • Awareness: Ensure that all members of the household are aware of the dangers of feeding onions and other toxic foods to dogs.
  • Safe Food Practices: Keep onions and all Allium-containing foods well out of reach of your pets.
  • Check Ingredients: Be vigilant about checking the ingredients of commercial dog foods, treats, and especially table scraps for onion or garlic content.


Onions are categorically unsafe for dogs and pose serious health risks.

Understanding the symptoms of onion poisoning and taking preventative measures can protect your dog from this dangerous food.

If you ever suspect your dog has ingested onions, immediate veterinary care is essential to mitigate the effects and ensure their well-being.