Deworming: How Often Depends on Your Dog
Once a year or every month? Europe's parasite guideline sorts dogs into four risk groups. How the groups work, where faecal tests fit, and why it matters.
Written by thecanineledger
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Europe’s main parasite guideline for dogs and cats puts it bluntly: “Studies have shown that 1–3 annual dewormings do not provide sufficient protection.” That line comes from the 2025 edition of the worm control guideline by the European Scientific Counsel Companion Animal Parasites, or ESCCAP (ESCCAP Guideline 01, seventh edition, 2025).
While the same guideline says some indoor dogs need treatment only once or twice a year, others need it every month. The right schedule depends on how your dog lives. This page explains the four risk groups, where faecal testing fits, and why worms matter for the people in your house too.
1. Why one schedule doesn’t fit every dog
ESCCAP’s starting point is that worm control is individual. “Deworming practices should therefore always be on the advice of a veterinary professional.”
Risk lasts for life. “Few parasite infections are strictly age-related”. The guideline asks for worm control “throughout its lifetime”, not just in puppyhood.
The evidence is thinner than the advice. The guideline admits that “There is surprisingly little information about the impact of treatment intervals on parasite burdens and environmental contamination.” What it does say is that “annual or twice-yearly treatments do not have a significant impact on preventing patent infection within a population.” A patent infection is one in which the dog is passing worm eggs.
2. The four risk groups
ESCCAP sorts dogs with a flowchart. The table below summarises it.
| Group | Which dogs | How often, per the guideline |
|---|---|---|
| A | Lives indoors, with very limited outdoor access. No contact with other dogs, no parks or gardens, no raw meat, slugs, snails or prey | 1–2 times a year against intestinal worms, or faecal tests |
| B | Goes outdoors but doesn’t roam, hunt or eat raw meat, and doesn’t eat slugs, snails or grass | 4 times a year against intestinal worms, or faecal tests |
| C | As group B, but eats slugs, snails or grass, or has contact with them | 4–12 times a year against intestinal worms and lungworms, or faecal tests. 4–12 times a year against tapeworms |
| D | Roams freely, mixes with other dogs, hunts or eats prey or offal, or is fed raw meat | 4–12 times a year against intestinal worms and lungworms, or faecal tests. 12 times a year against tapeworms |
If your vet can’t tell which group your dog is in, the guideline’s default is “at least 4 times a year.”
Higher-risk households. For dogs that share a home with small children, or with immunocompromised or elderly people, the guideline suggests monthly deworming or monthly faecal tests, “Depending on the risk assessment”.
Raw feeding. Dogs fed raw meat that hasn’t been cooked or deep-frozen “should be treated for tapeworms every 4 weeks.” The guideline says cooking to a core temperature of at least 65°C for 10 minutes, or freezing for at least a week at -17 to -20°C, prevents these infections.
Our note: We print the guideline’s treatment frequencies, but no products or doses. Take your dog’s risk group to your vet.
3. Faecal testing instead of routine treatment
It’s a recognised alternative. The guideline says regular faecal examination “can be an alternative to standard deworming advice if performed at the same frequency as the suggested treatments.” So a group B dog would be tested 4 times a year, not once.
Its limits.
- Eggs can still be shed between tests: “the excretion of infective eggs is still possible and cannot be prevented.”
- A negative result isn’t proof. Early infections, or low egg counts, can be missed.
- For tapeworms, “the reliability of detecting tapeworm infections using faecal sample tests is low”, with one exception. So for dogs whose risk can’t be clearly assessed, the guideline recommends treating against tapeworms “at least 4 times a year”, rather than relying on tests.
Some countries require it. Where routine treatment isn’t allowed by law, the guideline recommends regular faecal examinations instead.
Our note: The tapeworm line comes from a footnote about dogs whose risk can’t be assessed.
4. Puppies
The guideline recommends treating puppies against roundworms “from 14 days old”, then every two weeks until two weeks after weaning. Where the risk stays high, such as puppy playgroups, it suggests monthly treatment up to six months of age.
The mother should also be treated, at the puppies’ first treatment. The guideline describes treating pregnant bitches to reduce transmission to the puppies. That is a decision for your vet, and we haven’t summarised it here.
→ Puppy Farms and Pet-Store Puppies: What the Behaviour Studies Found
5. Why worms matter for people
Roundworms. “Toxocara roundworms have an elevated zoonotic potential.” A zoonosis is an infection that can pass from animals to people. In people, swallowed eggs can hatch into larvae that migrate through the body. “If larvae become blocked in the human eye, nerve tract and/or brain during migration, serious health problems can occur.”
Fox tapeworm. In parts of Europe, a tapeworm called Echinococcus multilocularis causes a serious human disease. The guideline says “Alveolar echinococcosis is a carcinoma-like disease, which without treatment can have fatal consequences.” In areas where it occurs, dogs that may hunt and eat small prey should be treated monthly.
What you can do.
- “The safe disposal of animal faeces is essential.” Pick up after your dog.
- Wash your hands after handling pets and before eating.
- Teach children to do the same, and wear gloves when gardening.
Our note: Tapeworm risk depends on where you live and travel. Ask your vet before travelling abroad with your dog.
6. Resistance, and why more isn’t always better
So far, resistance is rare in Europe. “To date, there have been virtually no proven cases of anthelmintic resistance to intestinal and extraintestinal nematodes in dogs and cats in Europe.” Anthelmintics are deworming drugs.
It has appeared elsewhere. The guideline notes resistance in some hookworm populations in Australia and the USA, and in heartworm larvae in the USA.
Frequent treatment has a cost. “Higher frequency of anthelmintic treatment could increase the selection pressure for resistance”, especially in kennels. For shelters and large kennels, the guideline recommends planned worm control with regular faecal checks.
7. Where this guideline applies
ESCCAP is a European body, and its advice is written for European conditions. Parasites and laws differ elsewhere. North American guidance, especially on heartworm, is different, and we haven’t reviewed it here.
Who funds it. The guideline describes itself as “research-based, independent advice.” ESCCAP’s website lists animal-health companies as sponsors. It says “ESCCAP appreciates the valuable support given by our Ruby and Sapphire Sponsors”.
Our note: The guideline publishes no conflict-of-interest statement, and its sponsors include companies that make deworming products.
→ Preventive Care Without the Upsell: What Your Dog Actually Needs
8. What we could not verify
| Commonly said | What we found |
|---|---|
| “Worm every dog every three months” | That’s the default only when risk is unknown. ESCCAP’s groups range from once or twice a year to monthly. |
| “Indoor dogs don’t need worming” | Not quite. The guideline still suggests 1–2 treatments a year, or faecal tests. |
| “A negative poo test means no worms” | Not always. Early infections and low egg counts can be missed. |
| “Once a year is enough” | Not for most dogs. The guideline says 1–3 treatments a year don’t give enough protection. |
| “Dog worms can’t affect people” | They can. Roundworms and some tapeworms can cause serious disease in people. |
Sources
- ESCCAP. Worm Control in Dogs and Cats. ESCCAP Guideline 01, seventh edition, June 2025. ⚠️ not peer-reviewed. Expert guideline; read in full (PDF)
- ESCCAP. Sponsors. ⚠️ not peer-reviewed. Organisation’s own page
Always confirm with your vet before acting on anything on this page.