Worms in dogs

Worms are parasites that live inside your dog’s body. Around 34% of dogs in the UK have worms. Most dogs will pick up worms at some point in their lives, but puppies, adult dogs who eat things outside and untreated dogs are most at risk.

Different types of worms live in different parts of the body. They cause health problems which range from mild to life-threatening and the illnesses they cause depend on their location. You can protect your dog against the risk of worms with regular preventive treatment using an effective wormer. Different wormers may be required for different worms.



How to know if your dog has worms

Two types of worms are most common in dogs – Intestinal worms and lungworms.

Intestinal worms include roundworms and tapeworms.


Roundworms and tapeworms

They usually live in your dog’s intestines. They may not cause any symptoms at all, so you don’t always know if your dog has worms.

Be prepared! Roundworms can grow up to 15 cm long in dogs. And even small types of tapeworms reach 50cm.

Tapeworms are like long ribbons made up of lots of tiny individual segments. Each segment contains between 30.000 and 1.000.000 eggs. Segments break off the adult tapeworm and pass out through your dog’s bottom in poo.



Symptoms of worms in dogs

Intestinal worms in adult dogs

Evidence your dog has intestinal worms includes:

  • Scooting or chewing under their tail
  • Spaghetti-like roundworms in poo
  • Small white things in poo that look like grains of rice are tapeworm segments
  • Tapeworm segments may also be in the hair around your dog’s bottom and tail

Intestinal worms consume your dog’s food and stop them gaining or maintaining weight. But they rarely cause severe illness, except in young puppies.

Symptoms of worms are usually due to tummy upset or poor nutrition. For example:

  • Poor body condition and weight loss
  • A dull staring coat
  • Developing a ‘pot belly’
  • Diarrhoea and vomiting, which can be severe in puppies and untreated dogs


Intestinal worms in puppies

  • Puppies with a lot of worms may develop breathing problems and pneumonia due to worm larvae in their lungs
  • Adult worms can completely block a small puppy’s intestine, causing life-threatening illness



Live inside your dog’s airways or in the blood vessels of their lungs and heart. You won’t see evidence of these worms in your dog’s poo.

Symptoms include:

  • Chronic coughs lasting weeks to months
  • Weakness and low energy
  • Breathing difficulty and pneumonia

Angiostrongylus is the most common lungworm in the UK.

Other lungworms are very rare in the uk but include:

Oslerus osleri

  • Lives in the windpipe (trachea) and larger airways
  • Transmitted from bitches to pups in saliva during grooming
  • Usually found in dogs under 2 years old

Crenosoma vulpis (Fox Lungworm)

  • Lives in windpipe and airways
  • Infection from eating slugs or snails or a creature which has eaten these



How do dogs get worms?

Intestinal worms

  • Eating soil contaminated with worm eggs from poo.
  • Grooming – licking up and swallowing unseen worm eggs on their coat
  • Eating dead wildlife, like rodents or rabbits
  • Scavenging
  • From an infected mum even before birth
  • From infected mum’s milk


  • When dogs eat roundworm eggs, the larvae hatch out and burrow out through intestine walls into tissues and blood vessels.
  • Larvae can migrate through the body into tissues like the heart, liver, eyes and lungs.
  • In adult dogs over 6 months old, their immune system stops the worms at this stage, and the halted larvae form cysts in tissues.

In puppies, pregnant bitches and dogs with weakened immune systems

  • Maturing larvae in the lungs are coughed up and swallowed, then re-enter the intestine as adult worms



  • Eating fleas that have eaten tapeworm eggs.
  • Eating dead wildlife, like rodents or rabbits

Worm eggs passed in poo can remain in soil for years and still be present long after the poo itself has gone. Dogs walking on contaminated soil get the eggs on their feet and fur and accidentally eat them when they groom themselves. For this reason, it’s essential that owners always clean up after their dogs.



Lungworm larvae from infected dogs or foxes are consumed by slugs and snails.

Dogs then get infected by:

  • Eating slugs or snails infected with Angiostrongylus larvae
  • Licking slime trails
  • Eating food or eating from bowls which are contaminated with snail slime
  • Playing with toys which have been left outside


Is my family at risk of getting worms?

Humans can get infected with roundworms from dogs. Around 5% of adults in the UK have antibodies to the dog roundworm, toxocara canis. This means that they have been exposed to the infection at some time in their lives.

Symptoms of illness are very rare but are caused by migrating larvae. Children are most at risk.

Symptoms include:

  • Vague symptoms include tummy pains, high temperature, itchy rash and coughs or wheezes
  • Specific eye symptoms can develop, including redness, pain and even blindness in one eye
  • There are around 50-100 eye cases each year due to Toxocara roundworms in the UK

How to reduce the risks

  • Pick up dog poo immediately, especially where children play
  • Wash your hands after handling dogs
  • Clean hands very thoroughly after handling puppies, who shed huge numbers of worm eggs
  • Clean bedding regularly



Diagnosis of worms in dogs

To find out if your dog has worms, your vet will:

  • ask you lots of questions about their lifestyle and symptoms
  • suggest blood and faecal (poo) tests


Vet treatment 

What to do if you think your dog has worms?

Vet treatment for worms in dogs

Talk to a vet or vet nurse for expert advice if you think your dog has intestinal worms.

  • Only a few wormers treat every stage of the worm’s lifecycle, so it’s important to choose the right one
  • Worming treatments are available as tablets, liquids, granules, paste or spot-ons
  • Many wormers can be purchased from larger pet supply stores or online retailers
  • Prescription wormers from vets tend to be stronger and more effective
  • ‘natural’ remedies are not suitable


Home treatment

Home treatment for worms in dogs

There are no home remedies to reliably treat or prevent worms in dogs.

However, home hygiene is essential to reduce risks of transmission and reinfection if your dog has worms.

  • Always clean up after your dog and dispose of poo carefully
  • Wash all washable bedding and soft furnishings your dog has laid on or walked over in soapy water at the highest possible temperature

If your dog eats a slug or snail or licks slug slime

  • Wash their mouth out thoroughly
  • Clean their teeth
  • Contact your vet to get a prescription wormer.



How to prevent worms in dogs

Roundworms and Tapeworms

Adult dogs

  • Worm your adult dog at least 4 times per year.
  • Wormers do not provide prolonged protection. Dogs can get reinfected immediately
  • Choice of wormer depends on your dog’s age, lifestyle and other health concerns
  • Worm dogs who eat dead things on walks or scavenge every 6 weeks or as advised by your vet
  • Discourage your dog from scavenging if possible


  • Worm puppies every 2 weeks from 2 to 12 weeks of age
  • From 12 weeks, worm growing pups monthly until 6 months old

Pregnant bitches

  • Worm pregnant bitches with fenbendazole (Panacur) daily from day 40 of pregnancy to 2 days after whelping
  • Panacur is safe for pregnant bitches
  • Panacur is effective against migrating larvae. This is essential to reduce transmission of worms to puppies before and after birth.
  • After pups are born, continue to worm your bitch at the same time as her puppies




  • Avoid leaving food bowls, water bowls and toys outside and wash them daily to remove any slug slime
  • Try to prevent your dog from eating snails or slugs in your garden or on walks
  • Use a prescription treatment that covers lungworm routinely if your dog is at risk (location and lifestyle)


When to worry

When to worry about worms in dogs

Contact your nearest vet if your dog:

  • Shows symptoms of collapse or breathing difficulties
  • Is coughing, with weakness, pale gums and bleeding in the white parts of their eyes


Joii can help with:

  • Choosing the right wormer for your dog
  • Understanding risks of worms


More about slugs and snails


  • Not all slugs or snails contain lungworm larvae,
  • a Countryfile statistic suggests, an average British garden is home to more than 20,000 slugs and snails. The risk of a dog encountering a lungworm host is therefore high.
  • Only snails and slugs carry infectious late-stage larvae. When a dog (or fox) eats a snail or slug (either on purpose or accidentally), the larvae migrate from the intestines through the liver and into the bloodstream. They then reach the heart, where they mature into adults. There they breed, and their eggs hatch into larvae which enter the airways. From the lungs, the larvae are coughed up, swallowed, and pass out of the body in poo. There they can infect passing slugs and snails.

Slime trails can also contain larvae, making anything the snail or slug has crawled over a risk. This includes bowls, toys and grass, which a dog may eat. Young dogs may be more at risk, purely because they may be more curious.

Although a dog can’t catch lungworm directly from another dog or fox, an infected fox (or dog) in the area can infect local snails and slugs, thus increasing the risk for everyone in the locality.

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