Worms in Dogs: Types, Symptoms and How Often to Worm
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A dog with worms usually looks perfectly well.
Fleas make themselves known, and ticks send you to the vet. Worms give you nothing to react to. Your dog can be carrying plenty of them and still bounce off the back step, clean the bowl and leave a normal-looking poo in the yard.
So there's never a moment where you think, right, time to do something about that. Worming slides down the list, and it's usually months later, at a vet visit, that someone asks when you last did it.
I'll take you through the four worms that matter here, what you'd actually notice, and how often to worm a dog that lives the way yours does
Heartworm is a different disease and has its own guide. One of these four is a bigger risk to your family than to your dog.
Four intestinal worms commonly affect Australian dogs, and most infected dogs show no obvious signs, so worming runs to a schedule rather than to symptoms.
A wormer clears what is in your dog on the day and leaves nothing behind, so a dog can be reinfected the following week.
Puppies need worming fortnightly until 12 weeks of age, which is far more often than adults.
Dogs with access to raw offal or carcasses need a praziquantel wormer every six weeks, because hydatid tapeworm can be fatal in people.
Most all-wormers do not cover heartworm, and most monthly all-in-one chews do not cover tapeworm.
Symptoms of Worms in Dogs
Watch for changes in condition rather than for worms, because a dog can carry a heavy burden and still pass a normal-looking stool.
The signs worth acting on:
Weight loss, or failing to gain, despite a normal appetite
A dull, dry or staring coat
A swollen belly, particularly in a puppy
Diarrhoea that keeps returning, with or without mucus or blood
Vomiting, occasionally with a worm in it
Pale gums, weakness or tiring easily
Lethargy in a dog that is normally busy
What you will actually see, and what you will not
Roundworms and tapeworm segments are visible. Hookworm and whipworm are not, at any stage, in any quantity. So "I have never seen a worm" rules out two of the four and tells you nothing about the other two.
On scooting: it is the sign everyone associates with worms, and most of the time it is anal glands rather than worms. Worth mentioning to your vet either way, but do not take a lack of scooting as a clean bill of health, or scooting alone as proof of worms.
If your dog's stools have changed and you are trying to work out what is normal, our dog poo chart and our guide to dog diarrhoea both help.
What Intestinal Worms Do to Dogs
Intestinal worms live in your dog's gut and take what passes through it, or take blood directly from the gut wall.
This matters especially in puppies. A young dog is growing on a tight nutritional margin, and a worm burden that an adult would shrug off can slow growth, thin the coat and swell the belly. Roundworm larvae reach puppies before they are born, crossing the placenta, and worms can be present in the intestines within a week of birth.
This is why puppies are wormed on a schedule that looks almost aggressive next to an adult's.
In an otherwise healthy adult dog, the usual presentation is nothing at all. No visible worms, no diarrhoea, a normal appetite.
How Dogs Get Worms
Most worms come from the ground, from fleas, or from the mother.
From soil and faeces. Roundworm and whipworm eggs, and hookworm larvae, survive in soil, grass and damp shaded ground. A dog picks them up by sniffing, licking paws, eating grass, or in the case of hookworm, through the skin of the feet. Eggs can persist in soil long after the dog that shed them has gone, which is why a park or a rental yard can be a source with no other dog in sight.
From fleas. Flea tapeworm gets in when your dog swallows a flea while chewing at an itch. It is the reason flea control and worming are the same job rather than two, and our guide to fleas on dogs covers the loop in full.
From their mother. Puppies are commonly infected before birth and again through the milk. A well-cared-for, wormed mother still produces puppies that need worming.
From scavenging. A dog that eats raw offal, gets into a carcass, or hunts is exposed to tapeworms that other dogs are not, including the one that matters most to your family rather than your dog. That is covered below.
The Four Intestinal Worms in Australian Dogs
| Worm | How your dog gets it | What you notice | What treats it |
|---|---|---|---|
| Roundworm | Soil, faeces, mother's placenta and milk | Pot belly, poor growth, spaghetti-like worms in vomit or stool | Any all-wormer |
| Hookworm | Larvae in soil, through skin or mouth, mother's milk | Pale gums, weakness, dark or bloody stool | Any all-wormer |
| Whipworm | Eggs in soil and faeces | Long-running large-bowel diarrhoea, often with mucus | Most all-wormers, check the pack |
| Tapeworm | Swallowing a flea, or eating raw offal or carcasses | Rice-grain segments near the tail or on bedding, often nothing | A wormer containing praziquantel |
Roundworm
The most common worm in Australian puppies and the one you are most likely to actually see. Adult roundworms look like pale spaghetti and turn up in vomit or stool. A pot-bellied puppy with a dull coat that is not growing as fast as its littermates is the classic picture.
Hookworm
Small and effectively invisible, but the most damaging of the four. Hookworms attach to the gut wall and feed on blood, and a heavy burden causes anaemia and weakness. In a puppy that can be life-threatening. The stool may look dark and tarry rather than obviously bloody, and our guide to blood in dog poo covers how to tell the difference.
Whipworm
Lives in the large bowel and causes diarrhoea that comes and goes for weeks rather than days, often with mucus and sometimes with fresh blood. You will not see whipworms. Our guide to mucus in dog poop covers what else produces that pattern.
Whipworm is also the worm most likely to be missing from a product's coverage list, so it is worth checking the pack rather than assuming an all-wormer handles it.
Tapeworm, and why one of them is different
Flea tapeworm is the common one and the least dramatic. Your dog swallows an infected flea, and weeks later you find what looks like grains of rice moving near the tail or dried onto bedding. It rarely makes a dog unwell. Clear the fleas, and it stops coming back.
Hydatid tapeworm is the one to know about, and it is barely mentioned on most Australian pages about worms.
A dog carrying hydatid tapeworm usually shows nothing at all. The risk is to the people in the household, because people are infected by hand-to-mouth transfer of tapeworm eggs from dog faeces, and in a person the parasite forms cysts in organs like the liver and lungs that can be fatal without treatment.
The cycle runs through livestock and wildlife. Sheep, cattle, goats, pigs, kangaroos and wallabies carry the cyst stage; dogs and dingoes carry the adult worm and shed the eggs. A dog gets it by eating raw offal or scavenging a carcass, which means a farm dog, hunting dog, a dog fed raw offal, or a dog that roams where stock lives is more susceptible.
Victorian Government guidance is that dogs in this group should be treated with a praziquantel wormer every six weeks, rotating with a broad-spectrum wormer. Drontal, which contains praziquantel, carries the same six-weekly instruction for hydatid areas on its own label.
One detail almost nobody mentions: for three days after worming a dog for hydatid, its droppings should be burned or buried deeply, with hands washed afterwards. The eggs being cleared are the infectious part.
How Worms Are Diagnosed and Treated
A faecal test identifies what your dog has, and the right wormer clears it within days.
Your vet checks a stool sample for eggs. It is quick and cheap, and it is the only way to know which worm you are dealing with rather than guessing.
It has one limit worth knowing. A worm has to mature before it starts shedding eggs, so a very recent infection can produce a clean result. If the signs point one way and the test comes back clear, your vet may treat anyway or repeat the test rather than rule it out.
Treatment itself is straightforward. An all-wormer covers the common intestinal worms in a single dose, and tapeworms need praziquantel specifically.
Formats run to tablets, chewables, spot-ons and pastes for puppies, and our dog worming treatments range is sorted by weight, which is the thing to get right. Under-dosing is a common reason a wormer appears not to have worked.
How Often Should You Worm a Dog?
A wormer clears what is in your dog today and leaves nothing behind to stop reinfection tomorrow, which is why the schedule does the work rather than the product.
This is the part most people get wrong, and it is not their fault. A flea or tick product keeps working for weeks after you give it. A wormer does not. It kills what is present and is gone, so a dog that walks back across the same ground the next day can pick up the same worms again.
Matching the frequency to your dog's life
Three months is a baseline, not a rule. It depends on your dog’s lifestyle, as exposure varies widely and the schedule should match it.
The suburban homebody that walks on footpaths and uses its own backyard sits at the low end. Three-monthly is genuinely enough.
The beach and bush walker meets more contaminated ground and other dogs' faeces. Three-monthly, done reliably, rather than three-monthly in theory.
The scavenger that eats things on walks, raids compost, or hunts is at the higher end. Talk to your vet about monthly.
The farm, hunting or rural dog with any access to offal, carcasses or livestock is the hydatid group. Six-weekly praziquantel, and worth being strict about.
Puppies sit outside all of this. Until six months, they are on their own schedule regardless of lifestyle, and our puppy flea, tick and worm range is filtered to products registered for the youngest and smallest dogs.
Always check with your vet to get guidance on which cadence is right for your dog.
And whatever interval you land on, put it in your phone. The most common reason a dog is under-wormed is not the wrong schedule; it is a schedule nobody is tracking.
A wormer is a treatment, not a shield. It clears the worms in your dog on the day you give it and leaves nothing behind, so a dog can be reinfected the following week. That is why worming runs to a calendar rather than to symptoms, and why a missed dose matters more than a late flea treatment does.
The Worms Your All-Wormer Might Miss
Most all-wormers treat intestinal worms only, so a dog on an all-wormer alone has no heartworm protection at all.
"All-wormer" means all intestinal worms, not all worms, and heartworm is not an intestinal worm.
| Product type | Roundworm, hookworm | Whipworm | Tapeworm | Heartworm |
|---|---|---|---|---|
| Intestinal all-wormer, 3-monthly | Yes | Usually, check the pack | Yes, if it contains praziquantel | No |
| Monthly all-in-one chew | Yes | Varies by product | Usually not | Yes |
| Flea and tick only | No | No | No | No |
| Heartworm-only preventative | Varies | No | No | Yes |
A three-monthly product cannot cover heartworm even when the active ingredient could. Heartworm prevention has to be given monthly to work. A wormer given four times a year is on the wrong schedule regardless of what is in it.
A monthly all-in-one chew usually leaves a tapeworm gap.
NexGard Spectra, for example, prevents flea tapeworm by controlling fleas but is not the product for an active tapeworm infection. Simparica Trio does not cover tapeworm either.
If you are weighing up two of the monthly chews, our comparison of NexGard Spectra and Simparica Trio sets out where they differ on worm coverage.
If your dog is in the hydatid group, a combination chew is not enough on its own and you need a praziquantel wormer such as Drontal alongside it.
Advocate is the other common monthly option, and it covers intestinal worms and heartworm but not ticks or tapeworm.
Our all-in-one dog parasite protection range shows what each combination actually covers.
Heartworm is a different disease
Heartworm is spread by mosquitoes, not picked up from the ground. The worms live in the heart and lungs rather than the gut, and the damage is done long before there is anything to see. It is prevented with a monthly or annual product, and our heartworm prevention range is separate from the worming range for that reason.
It is a bigger topic than a section, so our guide to heartworm in dogs covers the risk by region, how prevention works and what happens if it is missed.
Can You Catch Worms From Your Dog?
Some dog worms do infect people, and children are the most at risk, because of where and how they play.
This is worth understanding rather than worrying about. The risk is real, it is small in a household that worms on schedule, and the things that reduce it are all things you would do anyway.
Roundworm. Eggs shed in dog faeces need a couple of weeks in soil before they become infectious, which is why prompt pick-up matters more than anything else. Swallowed by a person, the larvae migrate through tissue. Children are most affected because of hand-to-mouth contact and sandpits.
Hookworm. Larvae in warm damp soil penetrate skin directly, which in people usually means an itchy, tracking rash on the feet. Bare feet on ground where dogs toilet is the exposure.
Hydatid tapeworm. The serious one, and the reason the six-weekly rule exists for at-risk dogs. Infection comes from eggs on the coat or in the environment reaching someone's mouth.
Victorian health guidance notes that young children are at higher risk, through closer contact with dogs and less careful hygiene.
What actually reduces the risk:
Worm on a schedule that matches your dog's exposure
Pick up faeces promptly, before eggs become infectious
Wash hands after handling the dog, and make sure children do
Cover sandpits when they are not in use
Do not feed raw offal, and keep dogs away from carcasses
Still Not Sure Which Product to Use?
The two questions that decide it are whether your dog needs hydatid cover, and whether you want worming folded into a monthly flea and tick product or kept as a separate three-monthly job.
If it is the second one holding you up, our guide to the best flea, tick and worm treatments for dogs sets the options side by side on weight range, what each one covers, and how often it is due.
Frequently Asked Questions
What do dog worms look like?
Roundworms look like pale spaghetti a few centimetres long and turn up in vomit or fresh stool. Tapeworm segments look like grains of rice, often moving, near the tail or dried onto bedding. Hookworms and whipworms are too small to see, so you cannot rule them out by looking.
What should I do if my dog vomits up a worm?
A worm in vomit almost always means roundworm and a burden heavy enough to be worth treating properly. Worm your dog with an all-wormer suited to its weight, and ring your vet if your dog is a puppy, is unwell, or keeps vomiting. Bring the worm if you still have it.
Do I need to worm an indoor dog?
Indoor dogs still need worming, though usually at the lower end of the range. Worm eggs come inside on shoes and paws, fleas find indoor dogs, and a dog that goes outside to toilet at all has ground contact. Three-monthly is the usual interval for a dog with a genuinely low-exposure life.
What happens if worms are left untreated in a dog?
Untreated worms cause weight loss, poor coat and ongoing diarrhoea, and in puppies a heavy burden can cause anaemia or a gut blockage that becomes an emergency. Adult dogs often cope for a long time without looking unwell, which is why the damage is usually found late rather than early.
Does an all-wormer cover heartworm?
Most all-wormers do not cover heartworm. They treat intestinal worms only, and heartworm needs its own monthly or annual preventative. A three-monthly wormer cannot protect against heartworm regardless of its ingredients, because heartworm prevention has to be given monthly.
Keeping Your Dog Worm-Free
Worming is the easiest of the parasite jobs to do well and the easiest to let slide, because nothing reminds you. Pick the interval that matches how your dog actually lives, set a recurring reminder, and check that whatever you are already giving covers what you think it does.
Our guide to the best dog flea, tick and worm treatments covers all parasite prevention options.
Veterinarian & Vets Love Pets Partner
BVSc
Dr Jack Ayerbe OAM is a distinguished Geelong veterinarian with over 50 years of experience, the founder of Newtown Veterinary Practice, and a dedicated advocate for animal welfare and ethics.
More articles from Dr Jack AyerbeReferences
This guide draws on:
The MSD Veterinary Manual, the global clinical reference for veterinarians, on intestinal worm biology, transmission to puppies and hookworm anaemia
The Victorian Department of Health on hydatid disease, the six-weekly praziquantel interval, and why children are at higher risk
The Better Health Channel, the Victorian Government's public health service, on the hydatid lifecycle and disposing of droppings after worming
Drontal Australia on hydatid tapeworm coverage and the six-weekly interval in affected areas
NexGard Australia on what a monthly all-in-one chew treats, and the distinction between preventing flea tapeworm and treating an active infection
