Dog - Garlic

What is garlic?

Garlic, the bulb of the plant Allium sativum, is a well-known herb and popular ingredient for cooking. It is supplied in raw form as the fresh bulb; as a liquid alcohol extract; or in gelatin capsules.

Why recommend administration of garlic to my pet?

In people, garlic is used as an antibacterial, antifungal, and to lower blood lipids and cholesterol. It is also used in an attempt to lower blood pressure and inhibit tumour formation.

In pets, garlic has been traditionally used to decrease internal and external parasites and as a supplement in the diet, particularly in animals with cancer or prone to infections. Flea control products for dogs and cats that utilise garlic abound on pet shop shelves. Do not use garlic products with cats. Use with care in dogs. Garlic can be toxic and cats are much more sensitive to the toxic effect of this health-giving bulb than dogs.

How much experience is there with the use of garlic in pets?

Garlic has been used in products for flea control in dogs and cats for many years. Do not use with cats.

How much research has been conducted on this supplement?

Despite the abundance of products that utilise garlic as a method of flea control in dogs and cats, research supporting its efficacy is lacking. Studies do show an anti-parasitic effect of garlic for internal worms in large animals and poultry, and an antimicrobial effect in pigs. One study showed that fresh garlic and powdered garlic cause stomach irritation in dogs when applied directly to the stomach wall.

A minimal amount of research indicates that garlic may be effective in killing giardia (an intestinal protozoan parasite) and dermatophytes (e.g. ringworm fungus) and sarcoptic mange (in combination with other herbs and applied externally). It also appears that garlic may reduce blood lipids (hyperlipidaemia) in dogs. Laboratory studies have illustrated an ability of garlic to inhibit tumour formation and lower blood pressure.

All of these effects must be considered marginal, and weighed against the potential for garlic to damage the red blood cells of dogs and cats. Do not use garlic products in cats. Use with care in dogs.

How safe is garlic?

Garlic can be toxic. The most important concern surrounding the use of garlic in dogs and cats is its ability to induce oxidative stress, resulting in damage to red blood cells, placing the animal at risk for anaemia. Larger doses are likely required for this effect, and garlic can probably be used safely at low levels provided red blood cell parameters are routinely evaluated. Concurrent administration of anti-oxidants may also protect against the red blood cell damaging effects of garlic. Dog breeds such as Akitas and Shibas, like cats may be more susceptible to garlic toxicity even at low doses.

Cats are more susceptible to the effects of garlic because their haemoglobin contains a greater number of sites for oxidation than are found in dogs.

Garlic can cause stomach irritation with mild symptoms of indigestion like burping and hiccups, or a picky appetite.

Garlic also may delay blood clotting and enhance the action of anticoagulant medication. It should not be used in animals with bleeding disorders.

Where do I obtain garlic and do I need a prescription?

Due to the potentially toxic nature of garlic with cats and dogs, we would advise you talk to one of the vets. Do not use garlic products with cats. We would be pleased to discuss using garlic as a supplement or as part of a flea control program. A prescription is not required.