GARLIC: HERB OR HAZARD?

We’ve been asked several times later if garlic is toxic to dogs. The internet gives conflicting advice with recipes for dog treat which contain garlic, but posters listing garlic as a potential poison…so today our blog is an attempt at the truth about garlic!

Herb or Hazard?

IS GARLIC A HERBAL MEDICINE FOR DOGS AND CATS?

Yes, it is! Garlic has a very long history of medicinal use. It is useful topically crushed in water to reduce infection in wounds (something done by Roman soldiers!). Taken internally it reduces the tendency of blood to clot and improves circulation so may be suggested for older animals. Garlic has been shown to help control internal parasites, and to improve cardiovascular health. Certain garlic compounds may even have anti-cancer properties. Garlic is a great appetite stimulant so is often added to homemade treats such as liver cake, and many holistic vets recommend making garlic a regular part of dogs diets.

IS GARLIC TOXIC TO DOGS AND CATS?

Garlic is definitely toxic too, as are all members of the onion family (Alliums). These plants contain sulphur compounds which cause oxidative hemolysis if there are more of them in a red blood cell than the antioxidant metabolic pathways in the cell can cope with. Dog red blood cells have low antioxidant activity, and the haemoglobin in cat red blood cells is two to three times more susceptible to oxidative damage than the haemoglobin in other species. Certain dog breeds, especially Japanese breeds, can have genetic differences in their metabolic pathways which make them more susceptible to the toxic effects of onions and garlic. Dogs and cats with an inflamed stomach lining may also be at higher risk of toxicity.

Symptoms of Allium toxicity are initially quiet vague with vomiting, diarrhoea, abdominal pain, and lethargy. After a few days gums may be pale, or even yellow due to the breakdown of the red blood cells. Anaemia will cause weakness, a high heart rate, and high respiratory rate. There is no specific treatment, but some dogs and cats recover with supportive care and anti-oxidant supplements.

Garlic should be avoided in pets on anticoagulant drugs, and should be introduced carefully to diabetic pets. Garlic should be stopped a week before planned surgery.

HERBAL OR HAZARD: IT’S A QUESTION OF DOSE

Consumption of  5 g/kg of onions or garlic for cats, or 15 to 30 g/kg for dogs can be toxic. An average garlic clove weighs 3-4g, so your dog or cat would need to eat quite a lot in one go to become sick. There have been cases of toxicity where pets have eaten garlic or onions at lower doses over long periods of time. These have included pets fed human foods where concentrated onion powder is often added for flavour.

If you are using herbal supplements containing garlic ensure you choose one designed for cats and dogs so that you know you are giving a safe dose, and never exceed the recommended dose.

If using fresh garlic a clove (3-4g) appears to be safe for a 20-25kg dog. I usually recommend giving garlic 5 days a week to reduce the risk of long term toxicity.

Dried garlic appears safe given at around 10mg/kg, but always consult a vet before adding any herb or supplement to your pet’s diet.