Are Slugs Poisonous to Dogs?

Slugs and snails are notorious for destroying gardens and flower beds. While they can be annoying to gardeners, they can also be dangerous to dogs. Slugs feed on gnarly things like parasite larvae that can be transferred to dogs if ingested. Learn why you should keep your dog away from these slimy critters. 

Are snails or slugs poisonous to dogs?

Common garden snails and slugs are not poisonous to dogs. However, dogs can get sick from eating them, which may expose dogs to bacteria, parasites, and toxins.

A slug is a mollusk (invertebrate) that moves around using a specialized muscle on the underside of its body, which is appropriately called a foot. Slugs and snails are essentially the same, except slugs lack the external shell that snails use for protection and retaining moisture. 

Slugs and snails feed on green leaves, fruits, flowers, and decaying plant material, making them a nightmare for some gardeners. They live in gardens, forests, or any area where moisture and plants are abundant. 

Encounters with slugs are not common for many dogs, because their access is typically limited to rainy periods. Snails and slugs hibernate when it’s too cold or too hot and dry — they also hide by blending in with their surroundings or burrowing in the soil or the crevices of rocks. But they do come out when it’s damp and cloudy. 

A few defense mechanisms help limit their exposure to accidental predators such as dogs. Snails can retreat into their shells if a dog gets too close. Slugs and snails can produce extra mucus when threatened, which smells and tastes bad to many dogs.

Can slugs be poisonous to dogs?

The bodies of land slugs are not poisonous to dogs, but some sea slugs contain toxins that are harmful to dogs. The grey side-gilled slug (Pleurobranchia maculata) has reportedly caused the deaths of dogs who ingested them after washing up on beaches in New Zealand.

These sea slugs contain tetrodotoxin, a neurotoxin found in puffer fish. There are also cone snails, a sea snail that uses a harpoon-like structure to sting predators and prey, injecting a paralyzing venom. Luckily, dogs are unlikely to encounter either of these dangerous creatures. 

Common toxins and parasites found in slugs

The main concern when a dog eats a slug is exposure to parasites, bacteria, or toxins that the slug already ingested. Slugs can transmit parasitic larvae that can infect dogs with lungworm. Slugs can also contain bacteria such as Salmonella, which can cause gastrointestinal disease. Meanwhile, slug bait is toxic to dogs, and secondary exposure can occur if a dog eats a slug that already ingested bait. 

Symptoms of poisoning or infection in dogs

Lungworm in dogs

Lungworm (Angiostrongylus vasorum) is a parasite that can cause respiratory disease in dogs. Slugs and snails eat lungworm larvae, which mature and become infective. 

Dogs can get infected with lungworm larvae when they ingest slugs or lick slug slime. After ingestion, the larvae travel to the heart and lungs, where they grow into adult worms and cause inflammation. Lungworm infection in dogs can cause respiratory disease, heart failure, or issues with blood clotting. In rare cases, the larvae can migrate to other areas of the body, causing issues in the brain, kidneys, or eyes. 

Not all dogs infected with lungworm will have symptoms. Clinical signs can show up one to three months after infection. Symptoms of lungworm in dogs may include:

• Coughing

• Nasal discharge

• Labored breathing

• Exercise intolerance

• Pale gums

• Lethargy

• Weight loss

• Blood in urine or stool

• Nose bleeds

Lungworm infection is often diagnosed by performing fecal testing or airway sampling to look for larvae. Radiographs of the chest are also used to determine the severity of lung disease. 

Lungworms can be treated with a dewormer, usually with multiple doses over a few weeks. Additional treatments, like steroids, may be recommended to address lung inflammation. Dogs who are severely affected may need to be hospitalized for supportive care. 

Slug bait poisoning in dogs

Dogs can be exposed to slug bait from either eating a slug that previously ingested the bait or eating the bait itself. Slug bait is often sweetened with molasses to attract slugs, and this sweetness can also attract dogs. Two types of slug bait are the most concerning: metaldehyde and iron phosphate. Metaldehyde-containing slug baits are more common and more toxic

Symptoms of metaldehyde slug-bait poisoning in dogs 

Metaldehyde interferes with the brain’s chemicals, leading to overstimulation. Dogs who ingest metaldehyde typically develop symptoms like muscle tremors and abnormal behavior within a couple of hours. The tremors can progress to uncontrollable seizures, which can eventually lead to hyperthermia and death. 

Symptoms of slug bait ingestion in dogs include:

• Anxious behavior

• Muscle tremors 

• Seizures

• Wobbly gait

• Heavy panting

• High heart rate

• Vomiting

• Diarrhea

• Drooling

Slug bait toxicity is determined through a combination of history (known access or ingestion) and clinical signs. Stomach contents can be frozen and sent off for testing, but that is rarely helpful when immediate action is required.

There is no antidote for metaldehyde poisoning in dogs, so treatment revolves around aggressive supportive care. Treatment often includes activated charcoal, fluid therapy, and medications for tremors and seizures. Dogs can recover from metaldehyde poisoning if appropriate treatment starts promptly. 

Iron phosphate slug bait in dogs 

Iron-containing slug baits are becoming more common and desirable because they are considered less toxic than those containing metaldehyde. But less toxic doesn’t mean nontoxic. Although iron phosphate is safer, it can still cause toxicity in dogs when consumed in large amounts.

Iron toxicity in dogs can cause gastrointestinal disease and severe liver damage. Treatment involves fluid therapy, stomach protectants, anti-nausea medication, and chelation (giving medication that binds to the iron in their body). 

Related article

Snail Bait Poisoning in Dogs: Symptoms, Treatment, and Prevention

It may protect your plants, but at what cost? A veterinarian explains how this toxin may keep your garden safe — but it’s extremely toxic to dogs. Here’s everything you need to know.

What can happen if your dog eats a slug?

Not every dog who encounters a slug ends up getting sick, but dog parents should reduce the risk as much as possible. Possible outcomes from a dog eating a slug include:

• Nothing

• Disgust or drooling from the bad taste

• Stomach upset from bacteria 

• Toxicity from slug bait

• A lung worm infection

Related article

Dogs Are Contracting an Illness From California Lakes and Rivers

Vets advise keeping your pup away from raw fish caught in rivers and lakes.

Steps to take if your dog eats a slug

If your dog eats a slug or a snail, make sure that they don’t have the opportunity to eat any more of them. This may require only walking your dog on a leash, blocking off your garden, or closely monitoring what they’re sniffing. Or you may need to tackle slug removal from your garden. 

If a slug was crawling on your dog’s food or water dish, be sure to wash it thoroughly: Lungworm larvae can be left behind. Monitor your dog closely for any immediate symptoms or behavior changes. Remember, lungworm symptoms can take weeks to develop, so let your vet know about the slug if your dog develops respiratory issues. 

When to consult a vet if your dog eats a slug

You should consult your vet if you know that slug bait has been scattered in the area that the slug was found, or if your dog starts developing symptoms of slug-bait toxicity after ingestion. See your vet if your dog develops persistent stomach upset or respiratory symptoms. 

Bottom line

Common garden snails and slugs are not poisonous to dogs, but they can transfer harmful parasites or toxins to dogs who eat them. Dogs who eat slugs risk developing a lungworm infection or toxicity from slug bait. Dog parents should take precautions to keep their dogs away from slugs and snails. 

FAQs

Can slugs cause long-term health issues in dogs?

A dog who gets a lungworm infection from eating a slug can experience chronic respiratory issues alongside lung inflammation.

What if my dog licks a snail or slug?

If your dog eats a snail or slug, watch them for immediate signs of slug-bait toxicity or future signs of a lungworm infection (respiratory disease). 

Can my dog die from eating a snail or slug?

The bodies of land snails and slugs are not toxic. But dogs can get a lungworm infection or metaldehyde (slug bait) toxicity from ingesting them, both of which can be fatal. 

Can dogs die from a lungworm infection?

An untreated lungworm infection can lead to severe lung inflammation and heart failure in dogs, which can be fatal. 

References

• ‌“Angiostrongylus Vasorum.” Companion Animal Parasite Council, capcvet.org/guidelines/angiostrongylus-vasorum.

• Buhl, Kaci J., et al. “Reports of Metaldehyde and Iron Phosphate Exposures in Animals and Characterization of Suspected Iron Toxicosis in Dogs.” Journal of the American Veterinary Medical Association, vol. 242, no. 9, 1 May 2013, pp. 1244–1248, pubmed.ncbi.nlm.nih.gov/23600781.

• ‌“Land Snails and Slugs of the Mid-Atlantic and Northeastern United States.” Carnegiemnh.org, 2022, carnegiemnh.org/mollusks/land-snails-slugs.

• ‌McNabb, Paul, et al. “Detection of Tetrodotoxin from the Grey Side-Gilled Sea Slug - Pleurobranchaea Maculata, and Associated Dog Neurotoxicosis on Beaches Adjacent to the Hauraki Gulf, Auckland, New Zealand.” Toxicon, vol. 56, no. 3, Sept. 2010, pp. 466–473, https://doi.org/10.1016/j.toxicon.2010.04.017. 

• “Snails and Slugs / Home and Landscape / UC Statewide IPM Program (UC IPM).” Ucanr.edu, 2018, ipm.ucanr.edu/home-and-landscape/snails-and-slugs/#gsc.tab=0.