Is Garlic Good or Bad for Dogs?

Jan 21, 2010Updated 8 months ago

Contradictory information exists on whether garlic is good or bad for dogs. Some dog enthusiasts swear by garlic as a health supplement and flea repellent for dogs while others claim its toxins can cause anemia, bleeding, and even death in dogs. In examining the facts, it seems that dosage may be the key.

Is Garlic Healthy or Toxic for Dogs? claims that garlic boosts immunities, fights infection, enhances liver function, lowers blood fats, and repels ticks and fleas, yet cautions that large doses given to dogs on a regular basis can cause oxidative damage to red blood cells leading to Heinz-body anemia and even death. They also caution that puppies under the age of 8 weeks, dogs scheduled for surgery, and those with pre-existing anemia should not be given garlic.

Drs Foster and Smith of are in agreement that garlic causes a breakdown of red blood cells in dogs although they allow that garlic in very small amounts in some commercial pet foods has not been shown to cause any problems. Their website states that a toxic dose is unknown and that cats are more sensitive to garlic than dogs are.

Mike Richards, DVM of advises that garlic is a member of the onion family, high in sulfur, and given in long term can cause anemic reaction and severe bleeding in dogs, especially small dogs and cats. However, small amounts used in cooking and flea medications do not seem to cause a problem.

Aleda M.Cheng, DVM CVA of uses garlic in canine cancer patients as a secondary treatment to traditional or holistic/herbal chemotherapy treatments. She feels that small amounts as an anti-cancer supplement outweigh the adverse effects but also confirms that large doses can cause anemia.

Veterinarians at the Wesley Chapel Veterinary Hospital in Florida claim that raw or cooked onions, onion powder, shallots, garlic or garlic powder all contain a substance that causes destruction of red blood cells resulting in potentially life-threatening anemia.

Veterinarians at the Lawrence Suwanne Animal Hospital in Georgia make the same claims adding that onions are more toxic than garlic.

Perhaps most revealing is the study published in the American Journal of Veterinary Research in November 2000. Four dogs were given measured amounts of garlic and four dogs received none. After only seven days, blood tests on the dogs taking garlic revealed decreased levels in hemoglobin, hematocrit, and red blood cell values. Heinz body formation, an increase in erythrocyte-reduced glutathione concentration, and eccentrocytes were also detected, although none of the dogs developed hemolytic anemia.

Veterinarians conducting the study concluded that garlic has the potential to cause hemolytic anemia and that food containing garlic should not be given to dogs.

Symptoms of Hemolytic Anemia

Pet owners who want to give their dog garlic should discuss dosage amounts with their veterinarian and whether the benefits are worth the risks. They should be aware of the dangers and keep an eye on the health of the dog. Symptoms to watch for include:

  • weakness, lethargy
  • discolored urine
  • pale or white gums
  • rapid breathing
  • vomiting
  • diarrhea
When red blood cells are destroyed, the body becomes oxygen-deprived and life-threatening conditions can develop rapidly. If any of these symptoms are observed veterinary attention should be sought immediately.

Related Reading

Readers who found this article helpful may want to read about other Homemade Dog Food Dangers and Onion Toxicity in Dogs.


American Veterinary Medical Association Journals