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Is Garlic Good or Bad for Dogs?

Let's take a look at what veterinary experts have to say about the vegetable and its oft-debated effects on dogs.

Marybeth Bittel  |  Apr 18th 2017


I come from an Italian family, so my personal relationship with garlic is what you might call “cemented into my DNA.” In the house where I grew up, garlic was used to season almost everything except breakfast cereal. So as you might expect, our family dogs were around the stuff on a regular basis. But it was always stored up high, out of the way. That’s because we’d been taught that garlic is harmful to hounds.

Over the years, I’ve asked my dog-loving friends for their opinions on garlic; and without exception, I’ve received the same decisive reply: “Garlic kills canines.” Yet curiously, I’ve often encountered the opposite insight while researching animal nutrition. Garlic is already considered a beneficial herb for humans — and apparently, several animal health experts believe it’s a worthy wellness ally for furry friends too. So really, what’s the story?

Reeking of confusion

Native to Central Asia, garlic is a species in the onion genus, Allium. That means its close relatives include onions, leeks, chives and shallots.  Make no mistake that onions are extremely toxic for your four-legged friend. That’s because they contain high concentrations of the sulfate ion thiosulphate, which can damage a canine’s red blood cells and lead to a condition called Heinz hemolytic anemia. In her book Complementary and Alternative Veterinary Medicine, veterinarian Dr. Susan Wynn points out that this same ailment can be triggered by benzocaine-based topical preparations and acetaminophen ingestion… and it can be deadly.

So garlic’s built-in “onion association” has prompted concern. Further complicating perceptions, however, a 2000 Hokkaido University study showed that four dogs fed steady amounts of garlic extract for seven consecutive days demonstrated red blood cell changes. While none of these dogs developed acute anemia or outward toxicity symptoms, wary researchers issued a garlic warning.

Similarly, if you were to research recent communications distributed by the ASPCA, Pet Poison Helpline and various pet insurance companies, you’d probably see garlic listed as a significant canine health hazard. In fact, during one interview with Pet Life Radio, ASPCA veterinary toxicologist Dr. Sharon Gwaltney-Brant noted that even small amounts of ingested garlic may cause underlying red blood cell damage.

Yet some animal herbalists like Rita Hogan, co-founder of Farm Dog Naturals, have emphasized that the Hokkaido study relied upon garlic extract fed in fairly excessive amounts. Interestingly, those same animal researchers eventually softened their original recommendation; noting that allicin, another compound found in garlic, can demonstrate positive effects on cardiovascular and immune function.

Dog sitting at table by Shutterstock.

Dog sitting at table by Shutterstock.

Pungent possibilities

Certain holistic animal care experts feel confident enough to praise fresh, food-based garlic outright — noting its antiseptic, anti-carcinogenic and anti-parasitic properties.

One such noted expert is holistic veterinarian Dr. Karen Becker, who has observed that fresh garlic, fed within six hours of crushing, can naturally help repel fleas and ticks. In the book New Choices in Natural Healing for Dogs and Cats, holistic veterinarian Dr. Thomas Van Cise cites limited servings of fresh garlic as a safe, healthful way to stimulate canine appetite. Additionally, holistic veterinarian Dr. Richard Pitcairn touts garlic as both a flea/tick repellant and an effective appetite stimulant. In his book, Dr. Pitcairn’s Complete Guide to Natural Health for Dogs and Cats, he observes that “not only is garlic tasty to many pets, it also helps to tone up the digestive tract and discourage worms and other parasites, including fleas. Garlic is particularly potent when it’s added fresh.” Other advocates include veterinarian Dr. Martin Goldstein, author of The Nature of Animal Healing; and veterinarian Dr. Shawn Messonnier, author of The Natural Vet’s Guide to Preventing and Treating Cancer in Dogs.

Before deciding whether you want to explore garlic as a dietary addition for your own dog, it’s crucial to remember that different pets may react in different ways to any food or supplement. That’s why careful consideration, plus a candid conversation with your own trusted vet, is often the smartest approach. It’s also why jumping in “whole hog” is a dangerous idea.

Given its demonstrated effect on red blood cells, for example, garlic should be avoided in pets with pre-existing anemic conditions; or in young puppies whose immune system is still developing. It should also off-limits when an animal is scheduled for surgery. Additionally, the Johns Hopkins Lupus Center notes that garlic can stimulate the human immune system. That means in humans (and theoretically animals as well), ingestion could potentially amp up an immune response that’s already in overdrive.

Seasoned with care

Let’s say you’ve researched the pros and cons of fresh, food-based garlic; discussed opinions with your vet; and decided that it might be worth a watchful try. Remember that careful dosage level and feeding frequency is imperative. It’s always wise to start very small, and monitor very carefully.

For example, Dr. Pitcairn’s book generally recommends a conservative fresh garlic feeding approach for canines, based upon body weight. Keep in mind that “one clove” of fresh garlic generally equals roughly 1 teaspoon of chopped garlic. The Complete Herbal Book for the Dog and Cat, by Juliette de Bairacli Levy, recommends this schedule:

  • 10 to 15 pounds – up to ½ clove daily
  • 20 to 40 pounds – up to 1 clove daily
  • 45 to 70 pounds – up to 2 cloves daily
  • 75 pounds and over – up to 2 ½ cloves daily

Animal herbalist Gregory Tilford, author of All You Ever Wanted to Know About Herbs for Pets, also notes that very limited amounts of powdered garlic can be used to help stimulate appetite. Tilford maintains that most dogs can safely consume up to 1/8 teaspoon of garlic powder per pound of food, no more than three times per week. Again, for safety’s sake, it’s always a good idea to build up to this very gradually.

Have you ever investigated garlic for your furry friend? Share your own insights here.