How often to deworm a dog or cat

How often to deworm a dog or cat as prevention

The ESCCAP guideline gives no single number for every animal. A vet sets the frequency from the pet's lifestyle: whether it roams unsupervised, hunts, eats raw meat, or shares a home with small children. The seventh edition of guideline GL1, Worm Control in Dogs and Cats, came out in June 2025 and kept the core rule of earlier editions.

If the risk cannot be assessed, dogs and cats are treated against roundworms, or checked with a faecal test, at least 4 times a year. ESCCAP applies the same minimum to tapeworms, because faecal tests detect them poorly. The guideline cites studies in which 1, 2 or 3 treatments a year gave insufficient protection. Even a 3-month interval does not guarantee that the animal won't start shedding eggs between doses.

The monthly interval for high-risk groups comes from the parasite's biology. After a dog or cat swallows Toxocara eggs from soil or eats an infected rodent, new eggs appear in its faeces a little over four weeks later. Monthly treatment kills the worms before the animal becomes infectious. For the fox tapeworm Echinococcus multilocularis this period is just under four weeks, so ESCCAP recommends treating rodent-hunting dogs every 4 weeks.

Russia's sanitary rules set a similar bar. SanPiN 3.3686-21, the federal sanitary code on infectious disease prevention, lists preventive and scheduled deworming of dogs in towns and villages at least once a quarter among its measures against toxocariasis. The clause is addressed to the authorities and organisations responsible for prevention in a territory and does not set an individual schedule. The number still matches the ESCCAP minimum.

Risk groups A, B, C and D: how many times a year

ESCCAP defines four risk groups for dogs and two for cats. The group comes from a flowchart in the guideline. It starts with whether the animal lives indoors or regularly runs off the lead, then looks at hunting, raw meat and contact with slugs and snails, which carry lungworms.

Group A is a dog that lives indoors, walks only on a lead, has no contact with other dogs, never goes to parks or gardens and picks nothing up from the ground. A group B dog gets 4 treatments a year against intestinal roundworms. Groups C and D add lungworms and tapeworms. Unsupervised roaming, hunting, eating prey, offal or raw meat, and a habit of eating grass or slugs push a dog into a higher group. The vet decides which branch of the chart a given dog follows, and the combination of factors determines whether it needs monthly tapeworm treatment.

ESCCAP considers raw meat safe once it has been heated to 65 °C in the core for 10 minutes or frozen for a week at −17 to −20 °C. Commercial pet food does not transmit these parasites.

How often to deworm an indoor cat

A cat that lives only in a flat, or goes out into a fenced yard and is unlikely to catch rodents, is group A in ESCCAP's scheme. It needs roundworm treatment 1 or 2 times a year, or a faecal test at the same frequency.

An indoor cat's risk is never zero. Toxocara eggs survive in soil for years, and according to Rospotrebnadzor, Russia's consumer health agency, flies and cockroaches carry them mechanically. If a child under 5 or 6 or an immunocompromised person lives in the flat, the guideline allows monthly treatment or monthly faecal testing even for a cat that never goes out.

A cat that hunts mice at a summer dacha is no longer group A. For cats that eat prey or raw meat, ESCCAP advises faecal testing or tapeworm treatment at least 4 times a year. Monthly treatment fully prevents shedding of fox tapeworm eggs, although cats shed them far less often than dogs. Fleas on an indoor cat are a separate reason to treat, covered below.

Deworming puppies under a year and kittens

Puppies pick up Toxocara before birth: larvae cross the placenta from about day 42 of pregnancy and later pass through the milk. Kittens are not infected through the placenta, only through milk, so their first treatment comes a week later. The early start matters because a heavily infected puppy can fall seriously ill before eggs show up in its faeces, which in puppies infected in the womb happens no earlier than day 16 of life.

1. 2 weeks (day 14)

   First roundworm treatment for puppies. The nursing bitch is dewormed the same day.

2. 3 weeks

   First treatment for kittens. The nursing queen is dewormed at the same time.

3. Every 2 weeks

   Repeat treatments until two weeks after weaning.

4. Up to 6 months

   Monthly, if the infection risk continues: puppy playgroups and classes, a kitten that roams freely.

5. After 6 months

   Frequency follows the adult animal's risk group.

The sources disagree here. In the sixth ESCCAP edition, monthly treatment up to 6 months was unconditional; the seventh ties it to ongoing risk. The seventh edition's table treats kittens every 2 weeks until weaning, while the main text of the same guideline says until two weeks after weaning. The Merck Veterinary Manual for cat owners has its own schedule: start at 3 or 4 weeks, repeat every 2 weeks until 3 months, then monthly until 6 months.

ESCCAP has no separate schedule for 6 to 12 months of age. An adolescent dog moves to the adult regime of its group. A puppy that goes to the park every day and plays with other dogs rarely fits group A, so the benchmark for it is at least 4 treatments a year.

Can you deworm a pregnant or nursing dog or cat

A pregnant female is treated for the sake of her litter. For bitches, ESCCAP describes two schemes with different drug classes: two treatments around days 40 and 55 of pregnancy, or daily treatment from day 40 until the second day after birth. A pregnant queen needs a single treatment about 7 days before giving birth, which prevents larvae passing to the kittens in milk.

Nursing bitches and queens are dewormed together with the first treatment of their young, 2 and 3 weeks after birth respectively. Mothers often develop an active infection at this point.

Products for these schemes are not licensed in every country. The Swiss version of the ESCCAP scheme states plainly that no products are approved there for pregnant bitches. A vet chooses the product and timing for a pregnant female.

Which dog and cat worms are dangerous to people

Toxocariasis is caused by larvae of the roundworms Toxocara canis and Toxocara cati. People are infected by swallowing eggs from soil, from poorly washed vegetables and herbs, from dirty hands and from animal fur. In humans the larvae never become adult worms; they migrate through organs such as the lungs, liver and eyes. Rospotrebnadzor reports 1,407 cases of toxocariasis in Russia in 2024, with children under 17 making up almost a third. The visceral form is most common in children aged 18 months to 6 years. The agency puts Toxocara infection in dogs at 40 or 50% and above, reaching 100% in rural areas.

Echinococcosis is rarer and more serious. Echinococcus tapeworms live in a dog's gut, while in humans their larvae form cysts, most often in the liver and lungs. According to the WHO, alveolar echinococcosis has a symptom-free period of 5 to 15 years and is fatal if untreated; Russia is among the regions where it occurs. Dogs pick up the fox tapeworm by eating rodents, and the cystic species from raw offal and carcasses of sheep, pigs and cattle. Echinococcus eggs are infective as soon as they are passed and are often found on a dog's coat.

The WHO names deworming of dogs as the basis of echinococcosis prevention. Rospotrebnadzor adds handwashing after contact with animals and soil, picking up faeces on walks and not letting dogs roam on their own. ESCCAP advises removing faeces daily, never flushing them or composting them, and keeping sandpits covered.

Faecal testing instead of a tablet: when it works

ESCCAP accepts regular faecal testing as an alternative to routine treatment for intestinal roundworms and lungworms, provided the tests are done as often as the treatments would be. In countries where routine deworming without a diagnosis is not accepted, the guideline recommends testing.

A negative result does not prove the animal is worm-free. Early in an infection there are no eggs in the faeces yet, and when there are few, the method falls below its detection limit. The animal may shed eggs between tests. Tapeworms, Echinococcus included, shed eggs intermittently, so ESCCAP keeps tapeworm treatment at no fewer than 4 times a year. Dipylidium is the exception: a coproantigen test detects it with high sensitivity.

Dogs that eat other animals' faeces can test falsely positive because eggs pass straight through the gut. A coproantigen test, or a repeat test after the dog has had no access to faeces before sampling, tells passage apart from infection.

Fleas and worms: why the treatments are linked

The flea tapeworm Dipylidium caninum is carried by fleas and chewing lice. A dog or cat is infected by swallowing an insect while grooming, and about 3 weeks later the worm starts passing segments. People can be infected too by accidentally swallowing an infected flea, but this is rare.

When fleas are found, ESCCAP recommends a single tapeworm treatment. Without flea control the effect is short-lived, because the animal gets reinfected. How often to treat for fleas and ticks is covered in the article on flea and tick treatment.

Should you deworm before a vaccination

The ESCCAP worm guideline does not mention vaccination and sets no interval between deworming and a jab. The requirement comes from vaccine leaflets. Instructions for several rabies vaccines registered in Russia say deworming is done 10 days before vaccination; some make it a condition, others a recommendation. Check the timing against the leaflet of the vaccine your vet uses.

Evidence is thin. In a 2024 study in the Journal of Feline Medicine and Surgery, 74 healthy kittens responded the same way to panleukopenia vaccination whether or not they carried intestinal parasites. The authors concluded that an infection without symptoms is no reason to postpone vaccination. Only clinically healthy animals are vaccinated, and vaccine leaflets state this separately.

See a vet without waiting for the scheduled date if a puppy or kitten is not growing well, has a swollen belly, a dull coat, diarrhoea with mucus or a cough, or if worms appear in vomit or faeces. In young animals a heavy Toxocara infection can turn into serious illness before a faecal test would show it.

How to keep a deworming schedule

The ESCCAP scheme depends on keeping the intervals. Skip two or three months at a time and "4 times a year" becomes 2 or 3, a frequency the guideline considers insufficient.

• The treatment date, the product and which worms it covers: roundworms, tapeworms or both.
• The animal's weight on the day: the amount of product depends on body weight, and puppies and kittens grow fast.
• Faecal test results with the date and method.
• The risk group and events that change it: summer at the dacha, starting to hunt, switching to raw food, a new baby, a trip.
• The next treatment date, set right after the current one.
• Flea treatments next to deworming: finding fleas means an extra tapeworm treatment.

If the pet's vet passport has a page for deworming records, copy the date and product there too, especially when the clinic gave the treatment. In faunely you can set up a recurring treatment with the interval you need, such as every 3 months or every 4 weeks, and get a Telegram reminder before the date.