Guides

Worming Your Dog: How Often and Which Worms Matter

Worming is one of those jobs that's easy to forget, because when it's working you see nothing at all. It's also one of the most important bits of routine care, and it comes up when I take on a new dog, because my forms ask what you use and when it was last given. Here's what the vets say about which worms matter in the UK, how often to treat, and how to choose a wormer that actually does the job.

• Adults every 1–3 months
• Prescription is more reliable
• Make sure it covers lungworm

TL;DR — key points

• The worms that matter most in the UK are roundworm, tapeworm and lungworm
• Roundworm and tapeworm rarely make adult dogs seriously ill but can be dangerous for puppies, and lungworm can be serious at any age
• Adult dogs usually need worming every one to three months, and puppies much more often
• Fleas carry tapeworm, and slugs and snails carry lungworm, so flea control and your dog’s habits both matter
• A prescription wormer from your vet is the most reliable choice, and there is no lungworm treatment available without a prescription
• Some worms can infect people, especially children, so always pick up your dog’s poo

Quick reference only — this is a shortened summary, not medical advice. For anything urgent, read the full guide below and contact your vet.

Why worm your dog at all?

Because you can't tell by looking. Adult worms, apart from tapeworm segments, are rarely seen, so a dog can have them with no sign at all, and the only certain way to know is to check a poo sample for eggs. Regular treatment is how you stay ahead of it. It matters most for puppies, who can get very poorly with roundworm, and for lungworm, which can be fatal in dogs of any age. It also matters for people, as the roundworm Toxocara canis can infect humans, with young children most at risk.

The worms to know about

Roundworm lives in the gut and looks a bit like spaghetti. In adults it rarely causes serious illness, but in puppies it can cause dehydration and blockages. Many puppies are born with it, and adult dogs can pick it up from soil, poo, raw meat and animal carcasses, or from licking contaminated things.

Tapeworm also lives in the gut. Dogs most commonly catch it by swallowing fleas, usually while grooming, which is why flea control matters (my guide to fleas covers that side). They can also catch it from raw meat, rodents and carcasses. You might see small segments like grains of rice in the poo or around your dog's bottom, and a dog may scoot or lick their bottom a lot.

Lungworm is carried by slugs and snails, and dogs catch it by eating them, often by accident while eating grass or drinking outdoors. Despite the name it travels around the whole body. PDSA describes it as a growing problem across the UK, and the signs can be vague, including coughing, fast or noisy breathing, weight loss, unexplained bruising or bleeding, and seizures. Contact your vet immediately if you spot any of these. Whipworm and threadworm exist in the UK but are relatively rare.

How often should you worm?

For puppies, PDSA's general rule is a first treatment at around three weeks old, repeated every two to three weeks until 16 weeks, though each product has its own guidelines, so check with your vet. Blue Cross says puppies often need worming until around six months old.

For adult dogs, PDSA says every one to three months is usually enough, and Blue Cross says at least four times a year. More often may be needed if your dog scavenges or hunts a lot. Blue Cross also says females need worming when they're pregnant or feeding pups, and 30 days after a season (see my guide to dogs in season). The right dose depends on your dog's age and weight, so it's worth weighing them rather than guessing.

Choosing a wormer

• Ask your vet which worms your dog needs treating for, as it depends on age, lifestyle and where you live.
• A prescription wormer, bought from your vet or an online pharmacy with a prescription, is far more reliable than non-prescription products, and can cover all the worms you need to treat.
• If you do use a non-prescription one, PDSA says the pharmacist-checked kind (known as NFA-VPS) tends to be more dependable than the supermarket kind, which it advises against.
• Make sure lungworm is covered. PDSA says there are currently no lungworm treatments available without a prescription, and Blue Cross says many common worming treatments aren't effective against it.

After worming, and keeping people safe

Most of the time you won't notice anything after a worming tablet. If your dog had a heavy burden you might see dead worms in their poo, but you often won't, as they can be digested. Contact your vet if your dog seems unwell or has diarrhoea after a tablet, and check with them whether to give another dose if your dog is sick soon after taking one.

Always clean up after your dog, especially in your own garden, where worm eggs can build up and stay a risk for years. Wash your hands after handling your dog and before eating. Most people who swallow roundworm eggs don't become ill, but in rare cases it can cause serious problems, which is why children are the main concern.

What I ask for when your dog stays or walks

My intake forms ask which wormer you use, how often it's given and when the last treatment was, so it's worth having the details to hand, and the same goes for flea treatment and vaccinations. It's on the list in my packing guide too.

Worming is quick and cheap compared with dealing with the illness it prevents. If you're not sure what your dog needs, ask your vet, and if you'd like to talk anything through, message me.

Where this advice comes from

If you'd like to read the original advice in full:

• PDSA on worms in dogs and lungworm in dogs
• Blue Cross on intestinal worms in dogs