Do Vets Advise Garlic for Fleas?

Garlic may be good for humans, but dogs may become ill by consuming too much.
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While many nutritionists tout garlic as a superfood for humans, it is potentially dangerous for your dog. Nevertheless, some dog owners, seeking alternatives to conventional pet care, feed garlic to their dogs in the belief that the resulting odor will repel fleas. Most veterinarians discourage dog owners from feeding garlic, but some holistic veterinarians endorse its use. Never feed garlic to your dog without first consulting a licensed veterinarian.

Active Ingredients

Garlic has a variety of purported health benefits for humans, including lowering blood pressure, lowering cholesterol and preventing some forms of cancer. Garlic also exhibits strong anti-microbial activity. One of the key components that delivers these benefits in humans is allicin. Unfortunately, garlic also contains a substance known as propyl disulfide, which can damage your dog’s red blood cells.

The ASPCA’s List of Toxic Foods

Along with several closely related plants in the genus Allium, such as shallots, onions, chives and leeks, garlic appears on the ASPCA’s list of foods that are toxic to dogs. The organization states that garlic can cause symptoms such as vomiting, anemia, blood in the urine, weakness and rapid heart rate. Their website suggests that pet owners who believe their dog has eaten garlic should call their veterinarian. However, Dr. Tina Wismer, senior director for veterinary outreach and education at the ASPCA’s poison control center, concedes that, while garlic is undoubtedly toxic at high quantities, it is usually harmless in small doses. Dr. Wismer suggests that the amount of garlic in a slice of garlic bread is unlikely to cause a problem, though a dog may become dangerously ill if he eats part of a raw garlic bulb. Nevertheless, she states that she is unaware of any research examining garlic for flea prevention.

Peer Reviewed Literature

On the Vetstreet pet health website, veterinarian Marty Becker refutes the notion that garlic controls fleas on dogs or cats, stating that there is no evidence of its efficacy. Most garlic-related literature published in peer-reviewed journals eschews garlic as a method of flea control. Keun-Woo Lee and several colleagues authored a study of the effects of garlic in dogs. Publishing their findings in a 2000 issue of the “American Journal of Veterinary Research,” the team found that garlic can harm dogs and it should not be a component of a dog’s diet. A 2007 paper, “Natural Approaches for Flea Control” by veterinarian Narda G. Robinson, devotes only two sentences to the subject of garlic, stating that it should not be fed to dogs.

Holistic Veterinarians

Many veterinarians who advocate alternative health care practices and treatments embrace the use of garlic to prevent fleas, though most discourage feeding garlic to puppies or dogs that already suffer from anemia or autoimmune diseases. Veterinarian Karen Becker, host of, advocates the use of garlic for flea control, though she does suggest consulting with a holistic veterinarian to determine the proper dosage for your pet. She goes further and suggests that only fresh garlic is appropriate, as garlic in tablet or powdered form lacks the medically important component allicin. Consult your vet before considering using it in any form for your dog.