Is Garlic Ever Safe for Dogs?

According to the American Veterinary Medical Association, the ASPCA, and the Pet Poison Helpline, garlic is toxic for dogs. The reason for this is simple, garlic contains thiosulphate, the same aliphatic sulfide found in onions, leeks, shallots and chives, which is what causes the toxicity in dogs.

Dogs are unable to break down and digest these foods. According to Dr.  Justine Lee, a board-certified veterinary specialist in both emergency critical care and toxicology and the CEO and founder of VetGirl, “garlic is “actually considered to be about 5X as potent as an onion.”

If garlic is so toxic for dogs, why are so many holistic veterinarians advocating the use of garlic and some dog food manufacturers adding it to dog food?

Garlic – good news for dogs

Many popular and well-respected holistic vets and herbalists prescribe the use of garlic routinely. They claim that the benefits of garlic for dogs outweighs the risks. They claim that the health benefits include:

• Natural antibiotic
• Supports the immune system
• Aids digestion
• Natural antifungal
• Natural antiviral
• Prevents intestinal parasites
• Prevents fleas and ticks

It is important to note that the studies of the benefits of garlic in dogs is primarily due to the studies of the benefits of garlic in people.  According to VCA Animal Hospitals: “Despite the abundance of products that utilize garlic as a method of flea control in dogs and cats, research supporting its efficacy is lacking. There are some anecdotal reports of an anti-parasitic effect of garlic in dogs and cats.  A minimal amount of research suggests that garlic may be effective in killing Giardia (an intestinal protozoan parasite) and dermatophytes (e.g. ringworm fungus) in dogs and cats. It also appears that garlic may reduce blood pressure in dogs and help minimize aminoglycoside (a particular type of antibiotic) toxicity in many species. Some laboratory studies have illustrated an ability of garlic to inhibit tumor formation and lower blood pressure.”

Garlic – bad news for dogs

Other vets, the ASPCA and the Pet Poison Helpline warn that garlic is toxic to dogs and should never be added to an animal’s diet. With the health of your dog at stake, it’s important to question both the positive and negative effects of garlic before feeding it your dog. Garlic toxicity in dogs includes:

• Nausea
• Vomiting
• Diarrhea
• Pale gums
• Elevate heart rate
• Weakness
• Bloody urine
• Exercise intolerance
• Lack of muscle coordination
• Excessive salivation
• Collapse

Advocates of garlic will argue that it would take a considerable amount of garlic to cause garlic poisoning in dogs, however, when recently consulting with a dog nutritionist, we were informed that garlic toxicity can build over time and there is no way to guarantee how much garlic a dog is ingesting in commercial dog food or how well each individual dog tolerates garlic. Furthermore, it can take several days for the toxic effects of garlic to appear.

Garlic’s deadly potential for dogs

There is no arguing that when a dog consumes garlic, it may be toxic. According to Veterinary Pet Insurance: “While mass consumption of garlic puts pets at high risk, your pet can also become poisoned after chronic ingestion of small amounts of garlic over a period of time.” Even worse than the above symptoms of garlic toxicity in dogs, invisible damage may be occurring in the dog’s red blood cells. Garlic and onion ingestion can cause a condition called hemolytic anemia, which is characterized by the bursting of red blood cells circulating through your pet’s body and gastroenteritis.  Garlic also may delay blood clotting and enhance the action of anticoagulant medication. It should not be used in animals with bleeding disorders.  

How much garlic is too much?

"Since garlic is significantly more concentrated than an onion, an even smaller ingested amount will likely lead to toxicosis—as little as one clove of garlic can lead to toxicity in dogs and cats. Please note that a pet’s weight, type of breed (Japanese dog breeds in particular including Shiba inus and Akitas) and prior health history can vary the toxicity level of ingested garlic. If you suspect your dog or cat has ingested garlic, you should contact your veterinarian immediately.”

Garlic overdose could vary depending upon the breed, size, weight and sensitivity of the dog.  Holistic vets typically suggest feeding: Half clove per ten pounds of body weight each day, chopped or grated. Two cloves maximum per day for a large dog is a good guideline.

• ½ clove for a 10 + pounds
• 1 clove for a 20 + pounds
• 1 ½ cloves for 30 + pounds
• 2 cloves for 40 + pounds

Always contact your vet or the Pet Poison Helpline for more information as this article is not a replacement for medical care.

Treatment for garlic toxicity in dogs includes:

• Call vet
• Possibly induce vomiting
• Transport to vet
• Activated charcoal
• Supportive care including IV fluids
• Oxygen therapy
• Blood transfusion

We are not suggesting that you feed your dog garlic and if you decide to, you should consult with your vet or animal nutritionist for professional information and feeding guidelines.