Are Slugs Poisonous to Dogs?

Are Slugs Poisonous to Dogs?

Slugs themselves aren’t technically poisonous to dogs, but they can carry something far more dangerous — lungworm, a potentially fatal parasite. If a dog eats a slug or even licks one while exploring the garden, they risk being infected. The threat doesn’t come from the slug’s slime or body, but from the parasites living inside them. In the UK, where lungworm is on the rise, this is a real concern for dog owners.

Why Do Dogs Eat Slugs?

Dogs are naturally curious, and some love to root around in the garden or nibble on strange things. Puppies are especially prone to putting anything in their mouths. Slugs and snails move slowly and often catch a dog’s attention. A dog might eat a slug out of boredom, playfulness, or simply by accident — especially if the slug is hiding in food bowls or chewing toys left outside.

What Is Lungworm?

Lungworm (Angiostrongylus vasorum) is a serious parasite spread through slugs and snails. When a dog eats or licks an infected slug, the lungworm larvae enter the dog’s body and migrate to the heart and lungs. This can cause severe illness, including breathing problems, coughing, bleeding disorders, weight loss, and even death if left untreated. The disease is spreading across the UK, especially in wetter, slug-friendly areas.

How Do I Know If My Dog Has Lungworm?

Lungworm symptoms vary and often appear gradually. Common signs include coughing, difficulty breathing, tiredness, poor appetite, unexplained bruising, and prolonged bleeding from minor cuts. In more advanced cases, seizures, collapse, or sudden death can occur. Because the symptoms can mimic other illnesses, it’s essential to speak to your vet immediately if you suspect exposure.

Is It Only Slugs That Carry Lungworm?

Slugs and snails are the main carriers of lungworm, but dogs don’t need to eat them directly to be at risk. Drinking from puddles or eating grass that’s been slimed can also lead to infection. Even playing with a toy left outside overnight where a slug has crawled over it can expose your dog. It's not the contact with the slime itself that poses the biggest risk, but whether it contains infected larvae.

What Should I Do If My Dog Eats a Slug?

If your dog eats a slug, don’t panic, but contact your vet straight away. They may recommend a preventative deworming treatment or lungworm test. Acting early can stop a possible infection before it becomes serious. If your dog is already on a monthly worming programme that covers lungworm, the risk is lower — but it’s still worth letting your vet know.

Can You Prevent Lungworm?

Yes, prevention is the best defence. Use a vet-prescribed worming treatment that covers lungworm — not all over-the-counter products do. Keep food and water bowls indoors, and clean outdoor toys regularly. Discourage your dog from eating slugs or snails and remove any you find in the garden. If your dog is prone to eating strange things, consider using a muzzle during walks in risky areas.

Is Slug Pellets Poisonous to Dogs?

Yes — slug pellets can be highly toxic to dogs. Many contain metaldehyde, which can cause rapid poisoning, leading to tremors, seizures, and death. If you use slug control products in your garden, choose pet-safe options and always read the label. Never leave pellets in areas your dog can access, and store them securely.

How Common Is Lungworm in the UK?

Lungworm is becoming increasingly common, especially in southern and western parts of the UK, where the climate is damp and ideal for slugs. Vets are seeing more cases each year, and many now recommend routine protection against lungworm as standard. It's no longer considered a rare problem — it's a growing risk for all dogs, particularly those who spend time outdoors.

Can Slug Slime Alone Harm Dogs?

Slug slime itself isn’t toxic, but it can be a carrier for lungworm larvae. If your dog licks a trail of slime — for example, on grass, toys, or food bowls left outside — they could ingest the parasite. While the slime won’t poison your dog in the traditional sense, it’s not something they should be consuming. It can also cause mild gastrointestinal upset, especially if they lick large amounts.

Are Certain Dogs More at Risk?

Yes — puppies and dogs that spend a lot of time outdoors are especially at risk. Puppies are more curious and likely to eat slugs or lick unusual things. Breeds with a high prey drive or those prone to scavenging (like terriers, retrievers, and spaniels) may also be more likely to encounter slugs or snails.

What Does Lungworm Do to a Dog’s Body?

Once inside, lungworm larvae travel through the dog’s bloodstream to the heart and lungs, where they mature and lay eggs. These hatch into larvae that are coughed up, swallowed, and passed out in the dog’s faeces — ready to infect more slugs. This internal journey can cause serious damage, including:

• Bleeding problems (due to disrupted clotting)
• Respiratory distress
• Neurological symptoms if the parasite spreads
• Sudden collapse or death in extreme cases

How Is Lungworm Diagnosed?

Lungworm isn’t always easy to detect. Vets may use a combination of:

• Faecal tests to detect larvae
• Blood tests to look for antibodies
• Chest X-rays if lung damage is suspected

Because early symptoms can mimic other conditions, vets will often treat based on likelihood and exposure history rather than waiting for confirmation.

Can You Catch Lungworm from Your Dog?

No — lungworm isn’t contagious to humans. It’s a parasite that follows a very specific cycle involving slugs, snails, and canines. You don’t need to worry about catching lungworm from your pet, but you do need to ensure your dog is protected so they don’t develop symptoms or spread the parasite further.

Is It Safe to Let My Dog Eat Raw Grass?

Eating a bit of grass isn’t usually harmful, but if the grass has slug or snail slime on it, the risk of lungworm goes up. If your dog eats grass regularly, especially in damp, shady areas or early in the morning when slugs are most active, it’s even more important to keep up with lungworm prevention treatments.

Summary

Slugs aren’t poisonous in themselves, but they can carry deadly parasites like lungworm. A curious dog licking or eating a slug might unknowingly be putting their health at serious risk. Prevention is key — use vet-recommended wormers, keep outdoor areas clean, and discourage slug-eating habits. If your dog does come into contact with a slug, don’t wait — call your vet and take the safe route. In a country where lungworm is on the rise, a little caution goes a long way.