Short answer
In most cases, yes. Veterinary and animal welfare organizations generally advise that dogs have some form of regular worm control, because intestinal worms are common and many infected dogs show no obvious signs. How often and with what depends on your dog’s age, lifestyle, location and the products already in use, so your vet is the right person to set the plan.
Why worming matters
Intestinal worms such as roundworms, hookworms, whipworms and tapeworms can affect your dog’s health in several ways:
- they can take nutrients and, in the case of hookworms, blood, causing weight loss or anemia
- they can cause digestive upset such as diarrhea and vomiting
- heavy infections can be dangerous, particularly for puppies
- some types can pass to people, especially children, so worm control helps protect the household too
How dogs pick up worms
Dogs can pick up worms by sniffing or eating contaminated soil or feces, by hunting or scavenging, by swallowing fleas that carry tapeworm larvae, and in some cases from their mother before or soon after birth. Heartworm is different and spread by mosquitoes, so is covered under flea, tick and heartworm prevention.
How often? What it depends on
You may see precise schedules online, and they differ between sources and countries. Be careful about copying one without checking, because the right interval depends on:
- Age: Puppies usually need more frequent worming than adults.
- Lifestyle: Dogs that scavenge, hunt, eat raw meat, visit dog parks or live with young children or other pets may be at higher risk.
- Location: Parasite risks differ by region.
- Products in use: Some monthly products include worm control; others do not.
- Your vet’s testing: Some vets favor routine treatment; others favor stool testing at intervals.
Ask your vet to recommend a schedule and write it down.
Puppies
Puppies are often treated for worms from a young age and repeatedly through early life, because roundworms in particular are very common in puppies. Your vet or the breeder’s records will indicate what has been given already. Never treat a young puppy with a product that is not labeled for its age and weight. Worming is usually discussed at early checkups; see our new puppy vet checklist.
Adult dogs and lifestyle risk
Adult dogs commonly continue to need some level of worm control. A low-risk indoor dog may need less frequent checks than a dog that roams, hunts or eats things it finds outdoors. Dogs that have fleas may also need tapeworm treatment. Discuss your dog’s habits with your vet in practical terms.
Does my monthly preventive cover worms?
Maybe. Some heartworm and combination preventives also treat or control certain intestinal worms, typically roundworms and hookworms and sometimes whipworms. Many do not cover tapeworms, so a separate treatment may be needed. Check the label and ask your vet precisely which worms your dog’s product covers. If you use a flea and tick product only, such as a spot-on like the one described in how Frontline works on dogs, do not assume it also controls worms.
Fecal testing or routine treatment?
Some vets recommend a periodic fecal test, which looks for worm eggs in a stool sample, as well as or instead of routine worming. Tests are helpful but not perfect, since worms may shed eggs only intermittently. Your vet will explain what suits your dog. If you suspect your dog already has worms, see how to get rid of worms in dogs.
Is there a downside to worming?
Wormers are widely used and generally well tolerated when given as directed, but there can be downsides:
- some dogs have side effects such as vomiting or loose stool
- the wrong product or dose can be ineffective or harmful
- some dogs, such as certain herding breeds, can be sensitive to particular medicines, so your vet’s input matters
- treating when it is not needed adds cost and exposure to medication
These are reasons to use veterinary guidance instead of guessing or doubling up products.
What happens if worms go untreated
Effects range from none noticeable to serious. Possible outcomes include poor growth in puppies, weight loss, a dull coat, diarrhea, anemia and, in heavy infections, life-threatening illness. Untreated infections also keep contaminating the environment, raising risk for other pets and people.
When to see a vet
Contact your vet if your dog has diarrhea, vomiting, weight loss, a swollen belly, scooting, visible worms or rice-like segments, or a cough. Get urgent help for a puppy that is weak, pale or refusing food. If you are considering a natural product instead, read our article on diatomaceous earth for deworming and discuss it with your vet first.