When to Deworm a Puppy? A Guide for Owners

The first deworming falls earlier than most owners expect — in the second or third week of life, which means it happens at the breeder's. The reason is straightforward: some roundworms pass from the dam to the puppies through the placenta and milk, so a litter can be infected before it ever leaves the whelping box. What follows sets out the schedule by age, the parasites most common in small-breed puppies, and what to do between doses.

Intestinal worms act faster in a young dog than in an adult, because immunity is still forming. They take a share of the nutrients from the food, irritate the gut, and in heavy infestations cause anaemia. The signs are often non-specific: a distended belly on an otherwise thin body, a dull coat, slower weight gain, intermittent diarrhoea. That is precisely why prevention runs on a calendar rather than on waiting for symptoms.

The benefits of deworming include not only improving the puppy's health but also its overall condition. Puppies that are regularly dewormed are more energetic, have a better appetite, and improved coat quality. Additionally, deworming reduces the risk of infecting other dogs and people, which is especially important for families with children. Regular veterinary visits allow for establishing a deworming schedule, which typically includes the first deworming of the puppy at 2-3 weeks of age, and then every 2-3 weeks until 12 weeks of age. It is also advisable to implement parasite prevention to minimize the risk of their occurrence.

• Parasites can lead to serious diseases such as anemia or enteritis.
• Regular deworming supports the development of the puppy's immune system.
• Controlling parasites reduces the risk of infecting other pets.
• Early treatment of parasites can prevent serious health complications.

The deworming schedule for a puppy should be tailored to its age. Puppies should be dewormed for the first time at around two weeks of age, as they may have parasites transmitted from the mother to the young. Subsequent dewormings should occur every two weeks until the puppy reaches three months of age. Some parasites, such as roundworms, can be particularly dangerous for young dogs, which is why regular deworming is essential.

After three months of age, deworming can be done every three months until the puppy reaches its first year. During this period, the puppy begins to explore its surroundings, which increases the risk of contracting parasites. Then, depending on the dog's lifestyle, regular deworming is recommended at least once every six months, and in some cases even every three months. Dogs that spend a lot of time outdoors or have contact with other animals may require more frequent deworming. It is advisable to consult with a veterinarian to determine the best schedule for a specific puppy.

• First deworming: 2 weeks of age
• Subsequent dewormings: every 2 weeks until 3 months
• From 3 to 12 months: every 3 months
• After 12 months: every 6-12 months depending on lifestyle

Puppies are susceptible to various types of parasites that can seriously affect their health. The most common parasites in puppies are: roundworms, tapeworms, and external parasites such as fleas and ticks. Roundworms are particularly dangerous because they can infect puppies while still in the womb or through the mother's milk.

• Roundworms (Toxocara canis) — the most common parasite in puppies, passed from the dam before birth. Signs are a distended belly, vomiting and poor weight gain; in heavy infestations they are visible in the stool.
• Tapeworms — transmitted by fleas and raw meat. Recognised by moving segments in the stool or around the anus, and by the dog dragging its rear along the floor.
• Fleas — besides the itching, they carry tapeworm, and in a puppy of a few weeks a heavy infestation can cause anaemia. A weekly check of the coat is enough to catch them early.
• Ticks — they transmit borreliosis and babesiosis. Check the skin after every walk through grass: ears, neck, groin and between the toes.

Symptoms of parasite infection can be varied and often subtle. In the case of roundworms and tapeworms, one may observe vomiting, diarrhea, as well as a decrease in appetite. Fleas can cause intense scratching and visible skin irritations. Ticks, besides being visibly present on the skin, can cause weakness and lethargy. It is important to pay attention to changes in the puppy's behavior, as they may indicate health problems.

Skipped prevention costs more than the infestation itself would suggest. With a heavy roundworm burden a small-breed puppy loses weight at a rate it does not make up later, and anaemia weakens the response to vaccination. Some of these parasites transmit to people, which settles the matter where there are small children at home. The schedule is set by a vet according to the dog's age and where it goes: a dog park, woodland and contact with other dogs all change the frequency.

The first dose is given at around two to three weeks of age — still at the breeder's — and repeated every two to three weeks until the twelfth week. The interval is not arbitrary: it matches the roundworm's development cycle, so each dose catches the generation the previous one missed. A dog collected from a breeder should have those dates in its health record; if they are absent, the cycle starts again from the beginning.

The recommended deworming products for puppies vary depending on the types of parasites that may be present. It is advisable to consult a veterinarian to select the appropriate product. Commonly used medications include pyrantel, fenbendazole, or praziquantel, which effectively eliminate the most common intestinal parasites. The veterinarian may also recommend testing for the presence of parasites, which will allow for a more accurate treatment plan.

• The first deworming should be done at 2-3 weeks of age.
• Subsequent dewormings should be performed every 2-3 weeks until the puppy is 12 weeks old.
• Always consult with a veterinarian when choosing a product.

Two things are settled with the vet before a dose: which product and at what dose, since dosing goes by body weight and a puppy's weight changes week to week. It is also worth saying where the dog goes and whether there are children or other animals at home — that changes which product is chosen. Bring the record of previous treatments together with the notes on your puppy’s vaccinations, so the vet can work from the full documentation.

Before administering the medication, make sure the puppy is in good condition. Observe its behavior, appetite, and overall health. If there are any concerning symptoms, such as vomiting or diarrhea, contact the veterinarian before starting the deworming process. It is also good to prepare a place where the puppy will take the medication to ensure its comfort and calm.

After deworming, it is important to monitor the puppy for a few days. Pay attention to its appetite, energy level, and any potential side effects. If vomiting, diarrhea, or other concerning symptoms occur, contact your veterinarian immediately. Keeping a journal to record changes in the puppy's behavior and health can help the veterinarian assess the situation.

• Monitor the puppy's appetite and well-being after deworming.
• Watch for any signs of allergies or intolerance to the medication.
• Keep the puppy calm, avoiding intense exercise for the first few days.
• Maintain cleanliness in the area where the puppy stays to minimize the risk of reinfection.

Below are the questions owners ask most often — about timing, about symptoms after a dose, and about what to do when the dog spits out the tablet. The answers apply to a typical healthy puppy; for a sick dog, or one recovering from surgery, the decision always rests with the vet.

• When should I deworm my puppy for the first time?
• How often should I deworm my puppy?
• What symptoms may indicate the presence of parasites?
• Is deworming safe for my puppy?
• What products are best for deworming?

A first dose at around two to three weeks, then every two to three weeks until the twelfth week, is the backbone of the whole schedule. After that the interval moves to once every three months, more often for dogs that scavenge outdoors or walk in woodland. Diarrhoea, vomiting, lethargy or a sudden change in appetite call for a faecal test rather than another dose on your own initiative: several of those signs have entirely different causes.

Deworming works when it is cyclical — a single dose clears the adult parasites but not the larvae, which hatch a few days later. Hence the repeats every two to three weeks in the first months and quarterly in an adult dog. Record the dates in one place alongside vaccinations: with two treatments a year it is easy to be a month out, and with six, a whole cycle.

Proper preparation for deworming includes not only administering the medication but also observing the puppy after the procedure. Owners should be aware of any symptoms that may indicate a reaction to the medication, such as vomiting or diarrhea. It is also important not to ignore visits to the veterinarian, who can help determine the best health prevention plan. Regular check-ups with the veterinarian are essential to monitor the puppy's health and adjust the deworming schedule to its individual needs.