Deworming Your Dog - Q&A

Estimated Reading Time 4 minutes
Deworming Your Dog - Q&A

How do you know if your dog has worms? And when should you deworm your dog? Dogs are at risk of being infected with many different types of intestinal parasites including roundworms, tapeworms and hookworms. They can become infected through several routes including other infected animals, their mother if she is infected while pregnant, or from eating worm eggs in infected feces, urine or grass. Here we answer your most common questions about deworming your dog!

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Roundworms are the most common intestinal parasites in puppies. These worms can be transferred to the pup from her mother during pregnancy and through her milk. The puppy can also become infected during the first months of life from contamination of their environment. Although less common, roundworms can also infect adult dogs, especially during times when their immune system may be suppressed.

Also known as ascarids, roundworms can range in size from 1-4 inches long. They are typically yellowish-white to brownish-red in color. The worms may be seen in the dog’s stools or vomit. Roundworm infection in dogs can cause varying signs including mild abdominal pain, diarrhea, and vomiting. Some puppies with heavy worm burdens may have a pot-bellied appearance or experience poor growth, dull coat, and lethargy.

It’s important to note that roundworms can infect people as well. Practicing good hygiene around contaminated areas or infected dogs is crucial.


While tapeworms are not as common as roundworms, dogs who hunt or are fed raw diets may be at increased risk of infection. A dog may also become infected with tapeworms by ingesting fleas while grooming.

Tapeworms, also known as cestodes, are flat and often long - over 6 inches in length! Infection with tapeworms rarely causes serious disease. Some dogs may experience loose stools or other digestive disorders. You may notice small, white, flat segments of tapeworm in the fur around your dog’s tail and hind end. Or you may see a chain of these white segments in the dog’s stool.


Three different types of hookworms are known to infect dogs: Ancylostoma caninum, Ancylostoma braziliense, and Uncinaria stenocephala. Ancylostoma species tend to be found in warm, humid climates while Uncinaria species are more common in cooler regions. A dog can be infected with hookworms by ingesting them from contaminated soil, penetration of the worms through the skin, or from their mother’s milk.

Hookworms are small - only about 1/8” long - and difficult so see with the naked eye. They can ingest large amounts of blood from the tiny vessels in the intestines. This may lead to severe anemia and weakness in an infected dog. Other symptoms include weight loss, bloody diarrhea, and dull, dry haircoat. Skin irritation and itchiness may be noticed on the skin where hookworm larvae have burrowed into the skin.

When Should You Deworm Your Dog?

In the past, all adult dogs were regularly dewormed. This approach is no longer recommended for several reasons. We know that each dog will have a different degree of exposure to intestinal parasites. Therefore, it makes sense to tailor their deworming protocol based on their risk factors. Additionally, there is no scientific evidence to support a fixed deworming protocol. A blanket deworming approach for all dogs increases the risk for worms developing resistance to commonly used drugs. Over time, this approach causes the drugs to become less effective in treating parasite infections.

Based on current scientific evidence, we now recommend that deworming protocols for adult dogs be based on the finding of parasites in fecal tests or if you have seen worms in your dog’s stool or vomit. Your veterinarian will likely recommend testing a fresh stool sample for parasite analysis. These tests may be repeated every 3 months, if necessary. Speak with your veterinarian if you have a strong suspicion that your dog may have intestinal parasites.

Puppies are usually dewormed by their breeder or at their first visit with the veterinarian by 8 weeks of age. Be sure to ask the breeder for details about your puppy’s deworming treatments. Depending on the deworming protocol recommended, your puppy may need to be treated weekly or monthly. Elimination of intestinal parasites should always be confirmed with a fecal test.

If traveling with your dog, always make sure to follow local and national requirements for pet import/export. Many foreign countries require dogs to be dewormed for tapeworm before arriving and after leaving the country. This must be performed and certified by an Accredited Veterinarian, documenting the treatment in your dog’s health certificate. Dogs without the correct documentation are not permitted to travel. Always check the USDA APHIS Pet Travel website for the most up to date information if you plan to take your furry family member along on vacation.

What Can You Do to Help Your Dog?

  • Discuss your dog’s risk for intestinal parasites with your veterinarian. They’ll be able to recommend the best deworming protocol for you.
  • Dogs that frequently go outside should be tested/treated every 3 months.
  • Dogs that hunt or are fed raw diets should be dewormed monthly.
  • Pregnant dogs should be dewormed during the pregnancy to reduce infection of the puppies.

If you suspect that your dog has an intestinal parasite infection, or you have questions about deworming your dog, please make an appointment with one of our FirstVet Vets.

Read more:

Parasites That Cause Diarrhea in Dogs

What You Need to Know About Vaccinating Your Dog

Puppy Socialization

Need to speak with a veterinarian regarding deworming your dog or another condition?

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Published: 9/3/2020
Last updated: 10/28/2021

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