Is garlic toxic to dogs?

Garlic, onion, leeks, chives and shallots all belong to the allium family. They share compounds that break down into substances which damage red blood cells, causing them to burst. Garlic is believed to be considerably more potent than onion, so a smaller amount can cause trouble.

There is no amount you can count on being safe. The risk depends on the dog's size and how much was eaten, and even a little garlic powder, which is concentrated, can matter for a small dog of 5 kg (11 lb).

Garlic bread, pesto, hummus, aioli, tzatziki, pasta sauces, curries, marinades, seasoned meats and many stock cubes all contain garlic. Garlic powder is often listed simply as seasoning or flavorings. Takeaway leftovers and roasting tin juices are common sources.

Black garlic, garlic oil and garlic salt carry the same compounds. Garlic-flavored dog chews sold online are sometimes marketed as natural, but they still expose dogs to allium compounds and are best avoided.

You may see garlic promoted online as a natural flea repellent or health supplement for dogs. There is no good evidence that it repels fleas, and regular dosing exposes dogs to the same toxic compounds. Your vet can recommend flea prevention that is proven and safe.

Early signs can include vomiting, diarrhea, drooling and belly discomfort. Anemia-related signs often follow after several days: lethargy, pale gums, fast breathing, weakness, collapse and dark red or brown urine. Some dogs show no early signs at all.