Overview
Even in clean homes with caring owners, worming puppies is a must. Puppy worms can be picked up from mum, the environment, or even from fleas. Though the signs aren’t always obvious, untreated worms can lead to serious health issues. Young puppies are especially at risk because their immune system and gastrointestinal tract are still developing. In this guide, we’ll show you how to spot the signs, choose the right treatment, and keep your puppy safe from these unwelcome guests.
The dangers of puppy worms
Puppies are at greater risk of worms than older dogs as their immune systems are still maturing, and they need every bit of nutrition to grow up strong. Worms steal those nutrients — and in some cases, can even harm your puppy’s gut or blood supply. The most common intestinal puppy worms are roundworms, hookworms, whipworms, and tapeworms, but there are some rarer worms which can cause serious problems for puppies, like lungworms and heartworms.
Puppy worms get picked up in a few different ways. They can catch them from mum (either in the womb or through her milk), from contaminated soil, faeces, or standing water, from swallowing infected fleas, or even from grooming, if they lick dirty fur or soil. Some parasites, like hookworms, can even sneak in through the skin if a puppy walks or lies on infected ground.
Once inside, worms can cause a range of health problems in puppies:
Poor or stunted growth as worms eat the nutrients your puppy needs
Gut blockages, especially with heavy roundworm burdens
Anaemia, particularly from blood-sucking hookworms
Breathing issues, as some worms travel through the lungs
Long-term damage to the gut lining
Lowered immunity, making puppies more vulnerable to other infections
In serious cases, a heavy worm burden can be life-threatening — especially for very young or underweight puppies. And the risk of worms isn’t just for puppies, as roundworms and hookworms can infect humans too. Children, older adults, and those with weaker immune systems are most vulnerable.
How do you know if your puppy has worms?
Many puppies won’t show any signs of worms unless the infestation is quite heavy. Even then, symptoms can vary depending on which worm they have. Some, like tapeworms or whipworms, may cause very mild symptoms early on, or even no symptoms at all. Still, there are some signs worth keeping an eye out for:
A bloated belly (often with roundworms)
Diarrhoea, sometimes with mucus or blood
Vomiting (occasionally with visible worms)
Scooting (when puppies drag their bottoms across the floor) or excessive bottom licking
Segments of worms in puppy poo or around the rear (they can look like grains of rice)
Weight loss or poor growth despite a good appetite
A dull or rough coat
Pale gums or tiredness (possible signs of hookworm-related anaemia)
Coughing or wheezing (especially with roundworms or lungworms)
Constant hunger, begging for food
Sometimes, the signs aren’t easy to see. A puppy might seem underweight, low on energy, or have persistent tummy troubles. And just because you can’t see worms doesn’t mean they’re not there. Many types are microscopic or only show up in poo occasionally, making them easy to miss. If your puppy has any of these symptoms — or hasn’t been wormed regularly — it’s best to check in with your vet, even if they seem fine otherwise.
Puppy worms diagnosis
If your puppy is showing signs of worms, your vet may suggest treatment based on symptoms alone, as regular worming treatments are recommended for most puppies anyway. If your puppy’s signs are less obvious, or it is necessary to find out more, diagnosis usually starts with a stool sample.
Your vet may use a method called faecal flotation — examining the sample under a microscope to check for worm eggs. Newer tests like PCR (which detects parasite DNA) and ELISA (which finds parasite antigens) can spot infections that traditional methods might miss. The Companion Animal Parasite Council (CAPC) recommends at least four faecal checks during a puppy’s first year, starting with their first vet visit. This helps catch parasites early and lowers the risk of reinfection. Testing your puppy’s stool sample can help confirm:
What type(s) of worm are present
How severe the infection is
The best treatment approach
A puppy’s symptoms, risk factors, and age can also play a role in diagnosis. Some puppies infected before birth or through their mum’s milk may show signs even before worms are visible in tests. That’s why vets often decide on treatment based on a mix of history, symptoms, and test results.
Some infections don’t show up in poo — especially in the early stages. On top of that, some worms don’t live in the gut, like heartworms who live in the heart and lungs. These worms need to be detected with a blood test — not a stool sample. These are all reasons why vets often suggest regular worming, even when no worms are visible.
Worming puppies safely
There are a few things to watch out for when it comes to worming puppies, but with a little awareness you’ll be able to give your puppy the protection they need without causing any issues.
Be careful of heavy worm burdens
In puppies with a heavy worm burden, killing too many worms at once can lead to side effects like vomiting or diarrhoea. In rare cases it can even lead to a gut blockage. This is why vets will sometimes recommend staggered treatments to reduce the risk of complications. If your puppy vomits soon after a worming dose, don’t give them another too quickly. It’s best to check with your vet before deciding what to do next.
Get the right product and give the right dose
It’s also important to weigh your puppy accurately before each treatment, as puppies grow so quickly that they may need different doses each time you worm them. Giving too little or too much can reduce effectiveness or cause unwanted side effects. Always check that your worming product is intended for puppies. Some products made for adult dogs can be unsafe or even toxic for young puppies or small breed puppies.
Keep in mind that some common dewormers don’t cover lungworm or heartworm. Prescription options are usually more effective and reliable than over-the-counter products, which may not tackle the full range of puppy worms. And finally, skip unapproved home remedies or over-the-counter treatments not designed for puppies. Always speak to your vet before starting anything new.
Treat mum if your puppies are nursing
If your puppies are still nursing, worming their mum is also a must. Roundworms and hookworms can pass through her milk, so treating her helps protect the litter and reduces contamination in the environment.
Join Pet Health Club
Members of Pet Health Club get worming treatments included. Your vet will be able to give your puppy worming treatments tailored to their specific needs, making the whole process stress-free. And it covers more than just worms — the Puppy Starter Package which new puppies get when signing up also includes treatment for fleas, ticks, and mites, as well as their starter vaccination course and microchipping.
Read more: Your puppy's first health check
How often do puppies need worming?
Once you’ve chatted with your vet and chosen the right wormer, it’s time to get your puppy on a regular schedule. Here’s a general guide:
Start at two weeks old
Then every two weeks until they’re eight weeks
After that, monthly until six months
This schedule helps tackle worms at different stages of their lifecycle. Most wormers only target adult worms, so repeat doses are key to clearing out larvae that may not be affected the first time. Larvae also sometimes move around the body before returning to the gut days or weeks later — so proper timing is crucial to stay protected.
Preventing puppy worms
Treatment is important — but preventing worms in the first place is even better. Here’s a list of simple tips to help reduce the risk:
Start worming early: puppies should begin at two weeks old and stay on a regular schedule through their first six months
Treat the mother during pregnancy and while nursing to reduce transmission through the placenta or milk
Use parasite prevention at recommended intervals all year round — not just in summer
Clean up poo promptly, especially in your garden or any shared spaces
Wash bedding and toys regularly to help prevent reinfection
Stay on top of flea control — when puppies get fleas, the fleas can give them tapeworms too
Don’t let your puppy go scavenging in the garden, and limit their exposure to slugs, snails, rodents, and raw meat — these can carry various types of worms
Avoid busy dog parks or communal areas until your puppy has had their starter vaccinations and been wormed
Practice good hand hygiene, especially in households with children, and keep sandpits covered to reduce human infection risk
Treat all pets in the household to avoid cross-infection
Store worming and flea products safely and administer them according to your vet’s instructions
Worm eggs are tough and can survive in soil for months or even years, making reinfection common without regular worming and good hygiene. That’s why staying on top of worming is so important — not just for your puppy, but to help protect your home and family too. Remember — Pet Health Club membership includes prevention from all sorts of parasites, including worms, tailored to your puppy’s requirements. Joining is the simplest way to stay on top of puppy worm prevention.
Ask your vet for help
If you’re finding it hard to get on top of a worm problem, your vet can offer tailored advice. For long-term peace of mind, Pet Health Club includes regular flea and worm treatment, vaccinations, healthy pet checks, and ongoing support to help keep your puppy in great shape. Use our Find a Vet tool to locate your nearest Pet Health Club practice.
Medically reviewed by Lizzie Youens, BSc(Hons) BVSc MRCVS
Published on 22/06/2025 • Reviewed on 22/06/2025