Worming schedule / United States
Puppy worming schedule in United States
American practice follows the Companion Animal Parasite Council, which uses fixed deworming ages rather than tying them to weaning, and then moves every dog onto a year round monthly broad spectrum preventive for life. Heartworm prevention is year round and starts no later than 8 weeks.
Worms, fleas, ticks and heartworm
| Treatment | From | How often | Notes |
|---|---|---|---|
| Deworming | 2, 4, 6 and 8 weeks | Every 2 weeks | CAPC: puppies should be routinely treated at 2, 4, 6 and 8 weeks of age, and the mother treated alongside them. Usually done by the breeder or shelter. |
| Monthly broad spectrum preventive | From 12 weeks, or as soon as the label allows | Monthly, for life | CAPC: puppies go onto a monthly preventive with efficacy against Toxocara as soon as label recommendations allow, and stay on it. There is no six month cut off in the American guideline. |
| Heartworm prevention | No later than 8 weeks | Monthly, year round | American Heartworm Society: start as early as the product label allows and no later than 8 weeks of age, on a year round program. Heartworm has been diagnosed in all fifty states. Test annually even on year round prevention. Many monthly products cover heartworm and intestinal worms together. |
| Flea and tick prevention | As soon after birth as the label allows | Monthly, year round | CAPC recommends year round flea and tick control for every dog, for life. It defers to the product label for the minimum age rather than publishing one, so the 8 week start above is a common label age, not a guideline figure. |
- CAPC anchors deworming to fixed ages, 2, 4, 6 and 8 weeks, rather than to weaning. If your puppy started late, CAPC's advice is to start the monthly preventive, deworm again two weeks later, then continue monthly.
- Many monthly products combine heartworm, intestinal worm, flea and tick cover, which is why your vet picks one product rather than four.
This is general guidance, your vet sets the actual schedule. Local disease risk, the products your clinic stocks and your puppy’s own history all change the plan. Take this page to your vet as a starting point, not as an instruction.
Common questions
When should a puppy start heartworm prevention?
As early as the product label allows and no later than 8 weeks of age, according to the American Heartworm Society, and then year round for life. Heartworm has been diagnosed in all fifty states, with the heaviest burden in the southeast and the Mississippi River Valley. Annual testing continues even on year round prevention, because no product is perfect and a missed dose matters.
Does an indoor dog need parasite prevention?
Yes. CAPC's position is that all dogs should be on year round flea, tick and heartworm control regardless of lifestyle. Mosquitoes come indoors, fleas arrive on people and on other pets, and a flea population established in a house is far harder to clear than to prevent.
Other countries
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Sources
- CAPC ascarid (roundworm) guideline: https://capcvet.org/guidelines/ascarid/
- CAPC hookworm guideline: https://capcvet.org/guidelines/hookworms/
- CAPC heartworm guideline: https://capcvet.org/guidelines/heartworm/
- CAPC flea guideline: https://capcvet.org/guidelines/fleas/
- American Heartworm Society, heartworm basics: https://www.heartwormsociety.org/pet-owner-resources/heartworm-basics
Last reviewed 2026-09-05.