Dogs eat all sorts of weird and wonderful things, particularly when snuffling around outside. Puppies are particularly curious and may end up eating things that they shouldn’t. But what can you do if your dog eats a slug? Do you need to worry?

Are slugs harmful?

The odd slug is unlikely to cause many problems in itself. They don’t taste particularly pleasant, so most dogs won’t actively seek them out, they are usually eaten by accident. This means that your dog or puppy may have also eaten whatever the slug was attracted to, such as rotten or mouldy food, which is more likely to cause digestive upset in your pet than the slug. Your dog might also have been eating grass or leaves that slugs are attached to, and some of these plants could cause stomach irritation too.


Whilst eating a slug is unlikely to cause too much damage, it could be harbouring a potentially deadly parasite known as Angiostrongylus vasorum (lungworm). This parasite is carried not only in the slug itself but also in the slug’s slime trail. The lungworm parasite has quite a complex life cycle which is summarised as follows – 

  • Slugs crawl around eating debris on the ground including faeces from an animal infected with lungworm larvae (such as a fox or dog)
  • The larvae exist inside the infected slug but can also be excreted in its slime trail
  • A dog accidentally eats a slug or licks its slime trail, and ingests the lungworm larvae
  • The larvae migrate through your dog’s body moving from its guts towards its heart and blood vessels
  • The larvae mature into adult lungworms and start laying eggs. These eggs are coughed up by the dog and swallowed down into the gut where they hatch into larvae.
  • Worm larvae will be excreted in your dog’s faeces, ready to infect more slugs and other animals.

Animals that are infected with lungworm can show varying symptoms of the disease. These symptoms include – 

  • Coughing
  • Laboured or rapid breathing
  • Haemorrhaging (bleeding) which could be hidden internally
  • Vomiting and diarrhoea
  • Weight loss
  • Reduced appetite
  • Lethargy
  • Collapse
  • Death

These signs can be non-specific and vague, so your vet may need to run various tests to try and identify if lungworm is the cause.

Read more here: Why lungworm is a threat to your dog

Do I need to take my dog to the vet?

If you suspect that your dog has eaten a slug then you should consult your vet for advice. Particularly if they are not on any form of regular preventative treatment for lungworm. They will likely recommend implementing some parasite products effective against this worm to prevent an infestation from taking hold. There are a few different effective prescription medications available including tablets and spot-on treatments. 

If your dog is showing signs of a lungworm infestation, then again you should contact your vet sooner rather than later. Dogs can become seriously ill, to the point of requiring intensive care in some cases. They could even die because of the side effects created by this parasite, so prompt treatment will give a better outcome.

How can I stop my dog from eating slugs?

It will be impossible to ensure your dog never eats a slug. But you can reduce the risk, and that of your dog coming across slime trails too.

  • Keep your dog’s toys indoors at night: slugs will crawl over everything especially at night when everything becomes damper. So, tidy your dog’s toys away each night to reduce the risk of slugs infected with lungworm crawling over them.
  • Don’t throw food waste or scraps into the garden where slugs may migrate towards them. Not only may your dog eat the waste food, but he may accidentally ingest a slug or two at the same time.
  • Don’t keep your dog’s food or water bowls outside, slugs may crawl across these leaving infected trails on a surface that your dog will then lick and eat off of.
  • Discourage your dog from eating plants and leaves, if possible, to reduce the risk of accidentally eating a slug too.
  • Teach your dog to come away from slugs and snails if you ever see them getting too curious. Train your puppy to ‘leave it’ and distract them with an interesting toy to play with.
  • You will be unable to guarantee that your dog will never eat a slug, so help protect your dog with a regular parasite treatment that is effective for lungworm – your veterinary surgeon will be able to advise you on this.


Whilst the slug is unlikely to cause too many problems for your dog, there is the risk that it carries a potentially fatal parasite known as lungworm. Prevention is far easier than cure, so make sure your dog has a regular treatment effective against this parasite and try to limit the amount of contact your dog has with slugs and snails generally. Always contact your vet if you have any concerns about your dog.

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