For more than 20 years, there has been a misconception among the dog parent community that garlic is toxic for dogs.  However, the claim was founded on a study conducted in 2000 that force-fed dogs via a nasogastric tube extremely high doses of garlic, doses that no dog would ever consume on its own! Not only is garlic not toxic for dogs, but it also has many medicinal benefits when provided at the correct dosa.

For thousands of years, garlic has been used as a medicine. Hippocrates, the legendary ancient Greek physician, used garlic to combat various illnesses, including ear infections, stomach disorders, and cancer. Scientific studies continue to elucidate the incredible therapeutic benefits of garlic for people and animals, including dogs.

The article entitled “Hematologic changes associated with the appearance of eccentrocytes after intragastric administration of garlic extract to dogs” was published in 2000 in the American Journal of Veterinary Research. 

Examining the details of the study will highlight the flaws. The study was conducted because many reports described hemolytic anemia in dogs induced by the consumption or experimental oral administration of onions (Allium cepa). Garlic is of the same genus, Allium, so there was a concern that it would cause hemolytic anemia if consumed by dogs.

The study consisted of eight healthy adult mixed-breed dogs randomly assigned to 1 of 2 groups, four control subjects and four test subjects. The mean body weight was 12-14 kg (26-30 pounds). The treatment group was force-fed via a nasogastric tube of 1.25 ml of garlic extract/kg, equivalent to 5 g of whole garlic per kg daily. The control group was given 1.25 ml of water/kg via a nasogastric tube. 

A typical clove weighs 4-7 grams, equating to the test subjects being forced to consume 60-70 grams or 12-14 cloves of garlic daily. No dog would voluntarily consume that amount of garlic, so they had to be force-fed with a nasogastric tube.

The study's conclusion stated that the red blood cells displayed markers of oxidative damage (the appearance of Heinz bodies and eccentrocytes). Because eccentrocytosis is a diagnostic feature of onion-induced hemolysis in dogs, the authors concluded that dogs should not be fed any garlic. However, the result section of the paper stated that no dogs developed hemolytic anemia.

Although the study revealed that garlic consumption at ridiculous levels induced changes in the red blood cells, even at that dose, it did not cause hemolytic anemia as assumed in the hypothesis.

Additional Study on the Effects of Garlic

Another study on the effect of garlic on dogs was conducted using beagles as the test subjects. The garlic was provided as an aged garlic extract (AGE), a process that renders garlic odorless and non-irritating by soaking fresh garlic in 15-20% alcohol for up to 2 months at room temperature. The extract from the solution is better at regulating blood sugar and provides more potent antioxidant properties than fresh garlic extract. AGE has also been shown to help prevent many diseases in humans and dogs.

The dogs in this study were given 45-90 mg/kg of the AGE extract of body weight for 12 weeks, which is equivalent to a ½-1 clove of garlic per day. The blood analysis performed after the 12-week trial revealed no adverse effects in the dogs and an upregulation of genes that regulate antioxidizing enzymes. This mechanism helps in disease prevention, including cancer and diabetes.

The medicinal properties of garlic for humans have been established in numerous peer-reviewed scientific studies. Garlic is rich in vitamins C, E, and K, and the minerals zinc, calcium, iron, potassium, magnesium, and manganese. Allicin, which is released when garlic is chopped or crushed, is the primary bioactive component of garlic.

Garlic benefits immune health, cardiovascular health, diabetes prevention and control, cancer prevention and treatment, and intestinal parasite control.

Allicin becomes unstable when exposed to air and heat. Fresh garlic, once chopped, should be fed within 20 minutes for your dog to receive the most therapeutic benefits.  Store-bought minced garlic should not be used as it is likely to contain additives that can negate the therapeutic benefits.

In human studies, it has been shown that there is an inverse relationship between the consumption of garlic and the incidence of stomach and colon cancer. The anticancer properties include the induction of enzymes, the inhibition of cancer cell differentiation and growth, and the promotion of apoptosis (natural cell death). 

Ajoene, the second most abundant compound in garlic, has been shown to inhibit cancer cell growth.

One of the complications of diabetes is hyperglycemia, or elevated blood sugar, which can ultimately affect the functions of several organs and tissues. Controlling the blood sugar level is the goal of managing diabetes in a dog. Garlic is known to significantly inhibit increases in blood glucose and improve glucose tolerance in animal models.

Many dogs will display the clinical sign of polyphagia or excessive hunger, as diabetes can cause the brain's dysregulation of hunger and satiety signals. Components in garlic have been shown to modulate hunger/satiety signals and reduce daily energy intake in people with diabetes.

The pancreas is the organ most affected by diabetes, as chronic hyperglycemia eventually causes the Langerhans islet β cells of the pancreas to fail. However, advanced studies have shown that the allicin in garlic protects the islet β cells and can reverse changes in the structure of damaged pancreatic cells.

International travelers are often advised to eat fresh garlic as a protectant against intestinal illness due to its antiparasitic properties. Garlic interferes with the enzymes essential to many common parasites and other pathogens that invade cells.

Garlic must be chopped or crushed to release its antiparasite component, allicin. Allicin has been reported to produce metabolites that interact with intestinal cells. Allicin has been challenging to study biochemically because, once formed, it quickly reacts with garlic's other components. 

Garlic can also be used for flea and tick prevention. Feeding garlic during flea and tick seasons can keep infestations under control. Over 2-3 weeks, garlic will build up in your dog’s natural coat oil and repel fleas and ticks. Continue to feed garlic throughout the flea and tick season.

Garlic has antibiotic and antibacterial properties that can help your dog fight viral infections, parasites, bacterial infections, and fungal infections. Garlic, crushed and mixed with coconut oil, can help with ear infections, ear mites, and the reduction of chronic inflammation.

Garlic’s Effect on the Cardiovascular System

Uncooked garlic combined with food lowers blood cholesterol and triglyceride levels in dogs, making it beneficial for breeds predisposed to hyperlipidemia, a disorder in which the amount of fats or lipids in the blood is elevated. Breeds predisposed to lipemia include Miniature Schnauzers and Beagles.

Ajoene, one of the components in garlic, has been shown to inhibit platelet aggregation in the blood, thus preventing the formation of clots or thrombi. It also inhibits the binding of fibrinogen to the activated platelets, again decreasing the risk of clots forming in the blood.

Due to its anti-coagulating properties, garlic should never be given to dogs with known blood disorders or if on blood-thinning medications. There are several genetic blood disorders in dogs. Von Willebrand's disease (vWD) is an inherited bleeding disorder in dogs caused by a deficiency in the specific protein, the von Willebrand factor, needed to help platelets (the blood cells used in clotting) stick together to form clots required to seal broken blood vessels. 

Factor II (prothrombin) disorders- although rare, they have been reported in Boxers and English Cocker spaniels.

Factor VII deficiency has been reported in Beagles, English Bulldogs, Alaskan Malamutes, Alaskan Klee Kai, Miniature Schnauzers, Boxers, and mixed-breed dogs. 

Hemophilia A (Factor VIII deficiency) is dogs' most common inherited bleeding disorder. 

Hemophilia B (Factor IX deficiency) is less common than hemophilia A. 

Avoid feeding garlic if your dog has been diagnosed with any blood disorder that interferes with blood clotting.

Puppies have a lower red blood cell mass and hemoglobin concentration than adult dogs due to the transition from fetal to postnatal blood cell development. Because studies have demonstrated that garlic can accelerate red blood cell turnover, it should not be given to puppies under six months of age to avoid any chance of anemia.

Because garlic bulbs and cloves can vary in size, it is best to measure garlic once it is chopped. However, in general, one clove, when chopped, will equal one teaspoon. The following chart details the correct dosage to use for adult dogs. 

A general guideline for the dosage of garlic is:

10 to 15 pounds – half a clove (or 1/2 teaspoon of minced garlic)

20 to 40 pounds – 1 clove (or 1 teaspoon of minced garlic)

45 to 70 pounds – 2 cloves (or 2 teaspoons of minced garlic)

75+ pounds – 2 and a half cloves (or 2 and 1/2 teaspoons of minced garlic)

Some dogs may refuse to eat garlic, especially if given raw. This may be a matter of selective feeding, a natural process in which dogs exercise choice over the type of food to consume. Dogs will eat foods that they feel are needed by their bodies. 

However, if the benefits of garlic are desirable, such as for natural flea and tick infestation prevention, there are ways to incorporate garlic into your dog’s diet. Using aged garlic extract (AGE) is a viable option if your dog refuses to eat garlic due to its pungent taste and smell. Although not ideal, mincing the garlic and mixing it with other components of your dog's meal will encourage her to eat it. 

Garlic has many medicinal benefits for dogs when provided at the correct dose.

Feed your dog the garlic within 20 minutes of dicing, mincing, or chopping to ensure a full therapeutic effect.

Fresh garlic or aged garlic extracts are the most therapeutic forms of garlic.

Hematologic changes associated with the appearance of eccentrocytes after intragastric administration of garlic extract to dogs 

Garlic and onions: Their cancer prevention properties - PMC 

Garlic and its Active Compounds: A Potential Candidate in The Prevention of Cancer by Modulating Various Cell Signalling Pathways 

Impact of organosulfur compounds in garlic on canine mammary tumor cells in culture  

Aged garlic has more potent antiglycation and antioxidant properties compared to fresh garlic extract in vitro - PMC  

Garlic-Derived Organosulfur Compounds Regulate Metabolic and Immune Pathways in Macrophages and Attenuate Intestinal Inflammation in Mice  

Antithrombotic and anticancer effects of garlic-derived sulfur compounds: a review  

Safety and efficacy of aged garlic extract in dogs: upregulation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and Nrf2-regulated phase II antioxidant enzymes  

 Is There Any Evidence to Support the Use of Garlic as a Wormer for Dogs and Cats in the UK?  

Effect of ajoene, the major antiplatelet compound from garlic, on platelet thrombus formation - ScienceDirect  

Garlic (Allium sativum L.) in diabetes and its complications: Recent advances in mechanisms of action 

Review of herbal medications with the potential to cause bleeding: dental implications, and risk prediction and prevention avenues  

Brady, C. (2020). Feeding dogs dry or raw? The science behind the debate. Farrow Road Publishing.

Breed-Specific Hematological Phenotypes in the Dog: A Natural Resource for the Genetic Dissection of Hematological Parameters in a Mammalian Species  

For more than 20 years, there has been a misconception among the dog parent community that <a href="https://feedreal.com/glossary/garlic">garlic</a> is toxic for dogs.  However, the claim was founded on a study conducted in 2000 that force-fed dogs via a nasogastric tube extremely high doses of garlic, doses that no dog would ever consume on its own! Not only is garlic not toxic for dogs, but it also has many medicinal benefits when provided at the correct dosa.

Examining the details of the study will highlight the flaws. The study was conducted because many reports described hemolytic <a href="https://feedreal.com/glossary/anemia">anemia</a> in dogs induced by the consumption or experimental oral administration of onions (Allium cepa). Garlic is of the same genus, Allium, so there was a concern that it would cause hemolytic anemia if consumed by dogs.

The study consisted of eight healthy adult mixed-breed dogs randomly assigned to 1 of 2 groups, four control subjects and four test subjects. The mean body weight was 12-14 kg (26-30 pounds). The treatment group was force-fed via a nasogastric tube of 1.25 ml of garlic extract/kg, equivalent to 5 g of whole garlic per kg daily. The control group was given 1.25 ml of <a href="https://feedreal.com/glossary/adenosine-triphosphate">water</a>/kg via a nasogastric tube. 

The dogs in this study were given 45-90 mg/kg of the AGE extract of body weight for 12 weeks, which is equivalent to a ½-1 clove of garlic per day. The blood analysis performed after the 12-week trial revealed no adverse effects in the dogs and an upregulation of genes that regulate antioxidizing enzymes. This mechanism helps in disease prevention, including cancer and <a href="https://feedreal.com/glossary/diabetic-ketoacidosis">diabetes</a>.

The medicinal properties of garlic for humans have been established in numerous peer-reviewed scientific studies. Garlic is rich in vitamins C, E, and K, and the minerals <a href="https://feedreal.com/glossary/zinc">zinc</a>, <a href="https://feedreal.com/glossary/calcium">calcium</a>, iron, potassium, magnesium, and manganese. Allicin, which is released when garlic is chopped or crushed, is the primary bioactive component of garlic.

One of the complications of diabetes is hyperglycemia, or elevated blood sugar, which can ultimately affect the functions of several organs and tissues. Controlling the blood sugar level is the goal of managing diabetes in a dog. Garlic is known to significantly inhibit increases in blood <a href="https://feedreal.com/glossary/glucose">glucose</a> and improve glucose tolerance in animal models.

Many dogs will display the clinical sign of polyphagia or excessive hunger, as diabetes can cause the brain's dysregulation of hunger and <a href="https://feedreal.com/glossary/satiety">satiety</a> signals. Components in garlic have been shown to modulate hunger/satiety signals and reduce daily <a href="https://feedreal.com/glossary/adenosine-triphosphate">energy</a> intake in people with diabetes.

The pancreas is the organ most affected by diabetes, as <a href="https://feedreal.com/glossary/chronic">chronic</a> hyperglycemia eventually causes the Langerhans islet β cells of the pancreas to fail. However, advanced studies have shown that the allicin in garlic protects the islet β cells and can reverse changes in the structure of damaged pancreatic cells.

Garlic has antibiotic and antibacterial properties that can help your dog fight viral infections, parasites, bacterial infections, and fungal infections. Garlic, crushed and mixed with <a href="https://feedreal.com/glossary/coconut-oil">coconut oil</a>, can help with ear infections, ear mites, and the reduction of chronic <a href="https://feedreal.com/glossary/inflammation">inflammation</a>.

Uncooked garlic combined with food lowers blood cholesterol and triglyceride levels in dogs, making it beneficial for breeds predisposed to <a href="https://feedreal.com/glossary/hyperlipidemia">hyperlipidemia</a>, a disorder in which the amount of fats or lipids in the blood is elevated. Breeds predisposed to lipemia include Miniature Schnauzers and Beagles.

Due to its anti-coagulating properties, garlic should never be given to dogs with known blood disorders or if on blood-thinning medications. There are several genetic blood disorders in dogs. Von Willebrand's disease (vWD) is an inherited bleeding disorder in dogs caused by a deficiency in the specific <a href="https://feedreal.com/glossary/catabolism">protein</a>, the von Willebrand factor, needed to help platelets (the blood cells used in clotting) stick together to form clots required to seal broken blood vessels. 

<a href="https://pubmed.ncbi.nlm.nih.gov/11108195/">Hematologic changes associated with the appearance of eccentrocytes after intragastric administration of garlic extract to dogs</a> 

<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4366009/">Garlic and onions: Their cancer prevention properties - PMC</a> 

<a href="https://pubmed.ncbi.nlm.nih.gov/30963982/">Garlic and its Active Compounds: A Potential Candidate in The Prevention of Cancer by Modulating Various Cell Signalling Pathways</a> 

<a href="https://pubmed.ncbi.nlm.nih.gov/8287376/">Impact of organosulfur compounds in garlic on canine mammary tumor cells in culture </a> 

<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5209668/">Aged garlic has more potent antiglycation and antioxidant properties compared to fresh garlic extract in vitro - PMC </a> 

<a href="https://pubmed.ncbi.nlm.nih.gov/35107883/">Garlic-Derived Organosulfur Compounds Regulate Metabolic and Immune Pathways in </a>Macrophages<a href="https://pubmed.ncbi.nlm.nih.gov/35107883/"> and Attenuate Intestinal Inflammation in Mice </a> 

<a href="https://pubmed.ncbi.nlm.nih.gov/16823096/">Antithrombotic and anticancer effects of garlic-derived sulfur compounds: a review </a> 

<a href="https://pubmed.ncbi.nlm.nih.gov/30497454/">Safety and efficacy of aged garlic extract in dogs: upregulation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and Nrf2-regulated phase II antioxidant enzymes </a> 

 <a href="https://www.veterinaryevidence.org/index.php/ve/article/view/163">Is There Any Evidence to Support the Use of Garlic as a Wormer for Dogs and Cats in the UK? </a> 

<a href="https://www.thrombosisresearch.com/article/0049-3848(92)90030-E/pdf">Effect of ajoene, the major antiplatelet compound from garlic, on platelet thrombus formation - ScienceDirect </a> 

<a href="https://www.tandfonline.com/doi/abs/10.1080/10408398.2022.2153793">Garlic (Allium sativum L.) in diabetes and its complications: Recent advances in mechanisms of action</a> 

<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6459456/pdf/13167_2018_Article_158.pdf">Review of herbal medications with the potential to cause bleeding: dental implications, and risk prediction and prevention avenues </a> 

<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3840015/">Breed-Specific Hematological Phenotypes in the Dog: A Natural Resource for the Genetic Dissection of Hematological Parameters in a Mammalian Species </a> 

The Truth About Garlic For Dogs

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