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Weed killer & dogs: how to prevent herbicide poisoning

Lawn chemicals and herbicides can be dangerous for our dogs, especially during the summer months when we’re all spending more time out in the garden.

To choose a pet-friendly weed killer this summer, it's important to read the labels carefully before making any decisions.

Let’s have a closer look at herbicide poisoning in dogs and what to do if your dog eats grass that’s contaminated with potentially harmful weed killer.

A brief summary...

What is glyphosate?

Glyphosate is a popular herbicide and is used on gardens all around the world to keep weeds at bay. It works by targeting actively growing plants only and is generally very effective. Sadly, when dogs ingest glyphosate – which usually occurs when they sniff or snack on grass that’s been sprayed with it – there can be some nasty consequences, including:

  • Heart rate problems
  • Difficulty breathing
  • Convulsions

Dog ate weed killer that contains glyphosate? Keep an eye on them and be prepared to contact your vet if you spot any symptoms.

Read more: Dog vaccinations: keeping your puppy happy and healthy.

Which other weed killer ingredients should I avoid?

As a general rule, when looking for pet-safe weed killer, keep clear of these ingredients if you have pets:

  • Disulfoton
  • Sodium Arsenite
  • Metaldehyde
  • Ammonium Sulfamate
  • Borax

Sounds like a lot of ingredients, right? Don’t worry, most reputable dog-friendly weed killers will be clearly advertised and if you’re in doubt, your vet will be able to advise.

dog in garden hiding face

Read more: Search for more advice from our vets

Symptoms of weed killer poisoning in dogs

If your dog displays any of the symptoms below, there’s a good chance they’ve ingested weed killer. Contact your vet if you notice:

  • Burns or sores around their mouth, nose or paws
  • A rash or itchy skin
  • Vomiting or diarrhoea
  • Strained breathing
  • Restlessness or abnormal behaviour
  • Fits or seizures
  • Excessive drooling

Note: these symptoms can belong to other conditions but if you’ve recently applied a weed killing agent to your lawn and your dog was fine until shortly afterwards, you probably know what the cause is!

What to do if you're concerned?

If you have any concerns, contact your vet right away. You may need to bring the chemical bottle with you so the vet can look closer at its ingredients.

It’s also helpful if you know how much contaminated grass your dog has eaten and when they ate it. Also – did they have a brief nibble or did they not stop eating grass until you told them to stop?

As ever though, prevention is better than cure!

When using any weed killing agents, make sure you follow the instructions on the back of the bottle very carefully. As you apply the chemical, keep your dog somewhere safe – preferably indoors – and give the treated area a chance to dry before letting your dog onto it.

Having a BBQ this summer? Check out our 7 BBQ safety tips for pet owners

Can weed killer kill dogs?

This is uncommon but, theoretically, weed killer could be fatal if your dog was to ingest a large amount of it. I.e. if they drank it from the bottle following a spillage.

To be extra safe, make sure you keep weed killer and other chemical-based household products somewhere safe and secure that your dog can’t access.

If you do spill chemicals, clean up the mess immediately and keep your dog away from the affected area until it’s dry.

Read more: Safety tips for keeping your pet safe


The seriousness of weed killer poisoning in dogs will depend on the amount of contaminated grass the dog has eaten. In much the same way, the treatment required will depend on how serious the dog’s symptoms are. The important thing is to be cautious and to contact your vet if you notice any of the symptoms listed above.

Need more info?

There are plenty of methods of keeping both your garden and your dog protected! For further information about weed killer poisoning or any aspect of your dog’s welfare, have a chat with your vet.

Find your nearest vet using our Find a Vet page, or speak to a vet online using Online Vets.