At this time of year, all we can think about is food! Whether it’s roast dinners, the boxset sofa snacks, the party nibbles, or even the New Year’s health regime, food is a hot topic! The dangers of chocolate and dogs are well publicised, and most owners know to keep the festive goodies and gifts well out of reach. However, did you know that other common foods can cause significant problems for our canine companions as well? 

In this blog, we’re going to look at the allium family, a group of vegetables and plants that have toxic properties to dogs (and cats!). This includes garlic, an ingredient which is found in many popular dishes and snack items. 

Read on to find out more about the problems garlic could cause and how to keep your dog safe.  

Why is garlic toxic to dogs? 

Garlic is part of the allium family, a group of vegetables and plants that also includes onions, chives and leeks. 

Allium species are plants which contain sulphur-containing oxidants. These are released by chopping, cooking or chewing, as well as the action of microbes in your dog’s digestive system. These oxidant compounds are absorbed into the body, leading to oxidative damage to circulating red blood cells. Rupture and destruction of these cells occur, which creates a condition known as haematolytic anaemia. 

The red blood cells are responsible for carrying oxygen to organs and tissues, so a significant drop in these can cause real issues. A severely anaemic animal will become weak and could collapse. Kidney damage can occur in affected dogs, and they may even die. 

Large amounts of garlic could cause symptoms with 24 hours, but if only moderate amounts are ingested, then symptoms may not be noticed for up to a week. 

How does garlic toxicity occur? 

Allium toxicity can occur when your dog accidentally eats garlic (or onions, leeks, etc.). All forms of garlic are toxic, including dried, powdered, cooked or raw. Dried or powdered forms are very concentrated, meaning that there is a higher risk of poisoning with these. 

Toxicity can occur if your dog raids your cupboards or bins, but also if you feed them table scraps or leftovers. Many dishes and snacks contain garlic or onions, so accidental poisonings are common. Wild garlic can also cause toxicity, so inquisitive pups that like digging up bulbs or chewing on plants are also at risk. 

How much garlic causes toxicity in dogs? 

For dogs, ingesting 15-30 g of onion per kilogram of bodyweight is enough to cause notable changes in their blood. Reported levels of toxicity for garlic vary greatly between sources. We do know that it is a particularly potent allium family member, though, being 3-5 times more toxic than onion to animals. This means that garlic toxicity is likely to occur at even lower doses than those quoted for onions. 

Smaller dogs will be more susceptible to toxicity due to their lighter body weight; for example, a Chihuahua eating a garlic clove is much more at risk of problems than a German Shepherd. 

It’s also worth noting that cats and some Japanese dogs are particularly sensitive to the toxic effects of garlic e.g. Shiba Inus, Akitas and Japanese Chin. 

Toxicity is therefore complicated and will depend on – 

  • The form of garlic eaten 
  • The amount of garlic eaten 
  • Genetic susceptibilities 
  • The size of your dog 

It’s therefore best to call your vet for advice if your dog has eaten garlic or any garlic-containing foods. 

What are the symptoms of toxicity? 

Symptoms of garlic toxicity may take a few days to develop, depending on the amount your pet has consumed, by which time your pet could be very ill. Signs of toxicity include – 

  • Stomach upsets, e.g. vomiting, diarrhoea and abdominal pain 
  • Changes in thirst 
  • Lethargy 
  • Reduced exercise tolerance 
  • Reduced appetite 
  • Pale gums 
  • Weakness 
  • Increased heart rate 
  • Increased breathing rate 
  • Changes in urination 
  • Collapse 
  • Death 

If you suspect your dog has eaten garlic, onions, shallots or leeks, you mustn’t wait until these symptoms develop. Recovery chances are much better with early intervention, so call a vet immediately. 

What should I do if my pet eats garlic (or onions, etc.)? 

If your dog has accidentally eaten garlic (or other alliums like onion, shallots or leeks), you must do the following – 

  • Immediately remove any remaining garlic or garlic-containing food so that your pet doesn’t consume any more. 
  • Try to estimate how much garlic your pet may have eaten. 
  • Call your vet straight away and tell them what has happened. 
  • Follow your vet’s advice, which may mean taking your pet into the practice for an examination and treatment. 

While many dogs will seem ok immediately after eating garlic, it is important to act quickly. Don’t watch and wait to see if symptoms develop, as this could have a negative effect on your pet’s prognosis.   

Also, you must never try to induce vomiting yourself at home. This could cause your pet harm, and it delays them from receiving proper medical attention. Prompt treatment from a vet is always recommended, which will give your dog the best chance of recovery. 

How is allium toxicity treated? 

Treatment will depend on how recently your pet has eaten the garlic and whether they are showing any clinical signs of toxicity. 

  • The vet will usually start by examining your dog, looking for issues like abdominal pain, pale gums or a fast heart rate. 
  • If your pet has eaten the garlic recently, within the last couple of hours, the vet may recommend inducing vomiting. This stops any further digestion and absorption of the garlic, reducing the risk of toxicity. Medication can be administered, which will trigger your dog to vomit. Your pet may also be given activated charcoal, which can also help to decrease absorption. 
  • Blood and urine tests may be recommended to look for signs of anaemia or kidney damage. 
  • Some dogs may need to be hospitalised for intravenous fluids (a drip) and observation, especially if they are showing clinical signs that they are unwell. 
  • Depending on their symptoms, they could require medication to help with nausea or seizures. A blood transfusion may also be needed in cases of severe anaemia. 

If they receive prompt veterinary care, most dogs recover well from garlic or onion poisoning. So, make sure to ring your vet immediately if your dog has eaten something they shouldn’t have. 

How can I prevent allium poisoning in dogs? 

To prevent accidents from occurring, you must always keep garlic, onions, shallots, leeks and chives well out of reach – remember that some dogs can reach the back of countertops better than you think or even open cupboards! 

You must also securely dispose of any food or leftovers seasoned with garlic and similar ingredients. Put them straight into a bin that your dog can’t access. 

Never be tempted to feed your dog any dishes or foods that contain garlic or onions. These include (but are not limited to) – 

  • Leftovers from onion or garlic containing dishes like shepherd’s pie, spaghetti bolognese, cheese and onion quiche, or onion soup. 
  • Garlic bread, or bread containing onions 
  • Savoury snacks coated in onion or garlic flavourings, including nuts, crisps or breadsticks 
  • Dips like onion containing salsa or sour cream with chives 

Keep your pet healthy by sticking to their normal good quality complete pet food and dog-safe treats. 

A quick note on other garlic and flea control 

You may have heard that garlic can be used as an anti-parasite treatment. There is no scientific evidence that garlic prevents fleas or other parasites, so it should not be used for this purpose. There are other, much more effective and safer products available. Speak to your vet for advice on the best anti-parasite treatment for your pet. 

Summary 

Allium species are toxic to dogs, including garlic, onions, shallots, leeks and chives. If you suspect your pet has eaten any of these, then you must contact a vet for advice immediately. In some cases, symptoms can take a while to develop – by which time your dog could be very unwell.   

Keep your dog safe by keeping these ingredients well out of reach and by never feeding human foods containing garlic, onions and similar. If you suspect your dog has eaten something they shouldn’t have, then call your vet for advice immediately. Prompt treatment leads to better outcomes, so don’t delay!