Most puppies are born with worms or get them within the first weeks of life. This does not indicate poor breeding. Roundworm larvae are dormant in the mother’s tissues and become active during pregnancy. They then pass to the puppy through the placenta before birth and again through her milk after birth. Regular deworming starting from two weeks old is the only way to keep ahead of these worms.
We can help you find a suitable schedule for your puppy based on its birthday using our puppy wormer schedule generator. We will provide you with more information about each treatment below as well as how the schedules change depending upon the age of your puppy.
Puppy Deworming Schedule Generator
Pick your puppy’s birth date and the guideline your vet is most likely to follow.
Puppy Deworming Chart
| Age | How often | What to cover |
| 2, 4, 6 and 8 weeks | Every 2 weeks | Roundworms and hookworms |
| 8-12 weeks | Every 2 weeks (Europe) or start monthly preventive (US) | Roundworms, hookworms, plus heartworm prevention where it exists |
| 3-6 months | Monthly | Roundworms, hookworms, whipworms, heartworm |
| 6 months and older | Monthly (US) or at least 4 times a year (Europe) | Add tapeworm cover if fleas or hunting |
| Adult dogs | Monthly preventive or every 3 months, plus fecal tests 1-2 times a year | Based on lifestyle and region |
Why Puppies Need Deworming So Early
The big ones are roundworms (Toxocara canis). The larvae remain dormant in the mother’s muscles, sometimes for years. When hormones from pregnancy wake up the larvae they cross the placenta into the puppy. Many more come to the puppy through the mother’s milk after birth. Therefore, by two weeks or three weeks old a puppy may already have adult worms laying eggs.
The problem with deworming medication is that one dose of dewormer does not eliminate all of the parasites. The medication kills the adult worms in the small intestine and colon, however the larvae that have migrated throughout the body will continue to develop into adult worms during the 1 – 2 weeks after being dewormed. Therefore treating every 2 weeks captures each group of developing worms as they become reproductive. This is why there are often 2-4-6-8 treatments recommended (i.e., at 2 weeks, then again at 4 weeks, etc.)
Common Worms in Puppies
| Worm | How puppies get it | Signs |
| Roundworm | From the mother before birth and through milk; eating eggs from soil | Pot belly, dull coat, diarrhea, vomiting worms that look like spaghetti |
| Hookworm | Through milk and through the skin from contaminated ground | Anaemia, pale gums, dark or bloody stools, weakness |
| Whipworm | Eating eggs from soil | Chronic diarrhea with mucus, weight loss |
| Tapeworm | Swallowing infected fleas or eating prey | Rice-like segments around the bottom or in stool, scooting |
| Heartworm | Mosquito bites | Usually no early signs; cough and tiredness later. Prevention is far easier than treatment. |
| Giardia (a protozoan, not a worm) | Contaminated water | Smelly, soft, fatty stools; needs different treatment |
What Dewormer Is Safe for Puppies?
Vets commonly prescribe Pyrantel Pamoate (safe to administer at two weeks of age) for roundworms and hookworms during the first 2-8 weeks, or Fenbendazole, which also covers whipworms and Giardia. However, once a puppy has reached the age of 8 weeks, most veterinarians in the US recommend using a monthly heartworm preventative that contains coverage for intestinal worms. In Europe, combination tablets that also cover tapeworms are common.
We’re deliberately not giving doses here. Dewormers are dosed by weight, puppies change weight fast, and the right product depends on your region. Get the product and dose from your vet, and weigh your puppy before every treatment.
A note for Aussiedoodles, Sheepadoodles and other herding mixes
The breeds that can carry the MDR1 (multi-drug resistance) gene mutation are primarily herding breeds such as Australian Shepherds, Collies, Shetland Sheepdogs and their crosses. The MDR1 mutation causes the dog to be overly sensitive to certain medications at higher than standard dose levels and one of those is Ivermectin. Standard doses of heartworm preventatives are generally considered safe for MDR1 dogs; however, if you are using a preventative at a dose level that is greater than the standard heartworm prevention dose, for example for mange, then it may not be suitable. A simple Cheek Swab Test is available to identify whether your puppy carries the MDR1 mutation. It would be advisable to discuss with your veterinarian about having this test done on your puppy if she/he has either Australian Shepherd or Collie/Shetland Sheepdog bloodlines.
Signs Your Puppy Has Worms
- Swollen, round belly while the rest of the body looks thin
- Diarrhea, sometimes with mucus or blood
- Vomiting, sometimes with visible worms
- Dull, rough coat
- Slow growth or weight loss despite eating well
- Pale gums (a warning sign of hookworm anaemia)
- Scooting or rice-like bits around the tail
Plenty of puppies with worms look completely normal, which is exactly why the schedule matters. Slow growth is often the only clue, so keep an eye on their numbers with our puppy weight calculator.
Can Humans Catch Worms From Puppies?
Deworming is important beyond just your puppy’s health. Roundworm eggs from infected animals can be ingested by humans through contaminated soil. Humans, especially young children who play outside and put their fingers in their mouth are at risk. Although extremely rare, roundworm larvae can migrate to the eye or internal organs. Hookworm larvae can also enter the body through the skin of humans.
- Pick up dog poop straight away, before eggs become infective (which takes a couple of weeks)
- Wash hands after handling your puppy and after gardening
- Cover sandpits
- Keep up deworming for life, not just in the puppy months
Side Effects After Deworming
Most pups have NO adverse reactions to deworming. Some pups will develop a slight case of diarrhea, vomit once, and then pass small amounts of dead worms in their stools for a couple days, which is a normal occurrence. If your pup is lethargic, vomiting frequently or has a heavy load of parasites that makes them uncomfortable, contact your veterinarian immediately; as an occasional circumstance with a high parasite load can sometimes cause intestinal obstruction.
Frequently Asked Questions
At 2, 4, 6 and 8 weeks old, then either monthly with a heartworm preventive (US) or every 2 weeks until 12 weeks and monthly until 6 months (Europe).
Every 2 weeks until 8-12 weeks, then monthly until 6 months. Adult dogs need monthly prevention or at least four treatments a year depending on where you live.
Following a vet schedule is safe. Overdosing a single treatment or mixing products can cause side effects, so stick to one product and the correct weight-based dose.
Heavy worm burdens can cause poor growth, anaemia, diarrhea, intestinal blockage and, in young puppies, death. Worms can also spread to people in the home.
Yes. Treating the mother at the same time as the puppies, and in late pregnancy if your vet advises, reduces the number of worms passed to the litter.
Yes. Dead or dying worms may appear in the stool for a day or two after treatment.
Yes. Most puppies are born with roundworms, and fleas, soil on shoes and other pets can bring in more.
Most vets recommend starting by 8 weeks old in areas where heartworm exists, and giving it every month.
Usually yes. Many vets do both at the same puppy visit.
Vet note: Written and reviewed by Dr. Muhammad Usman, DVM, based on CAPC and ESCCAP guidance. Product choice and dosing should always come from your own veterinarian.
More tools: Puppy Vaccination Chart · Puppy Schedule · Puppy Feeding Schedule Calculator
