How to Identify Roundworms in Dogs and Puppies.

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How roundworms can affect your dog or puppy.

 A German shorthaired pointer hunting in the grass.

Nearly all dogs will become infected with roundworms at some stage in their lives — dogs can pick these intestinal parasites up remarkably easily. Because roundworms in particular can also affect you and your family, it’s important to know what to look for. Here’s what you need to know about roundworms in dogs to help keep your dog free of this intestinal worm.

What Are Roundworms in Dogs?

Roundworms are one of the most common intestinal worms in dogs. These parasites live freely in an infected dog’s intestine, feeding on partially digested food by absorbing nutrients through their skin. They are tubular, white or light brown, spaghetti-like worms that may be several inches long.

How Do Dogs Become Infected with Roundworm?

While dogs of any age can get roundworms, this parasite is most common and most serious in puppies, which can be born with the infection passed through their mother’s placenta or contract it from their mother’s milk.

However, adult dogs are easily infected, too. They can accidentally swallow roundworm eggs in dirt, plants or stool when they sniff outside or if they eat an infected rodent or bird.

What Are the Signs of Roundworm in Adult Dogs?

Unfortunately, you may not be able to tell whether your dog has roundworms; adult dogs often won’t show signs of a roundworm infection, though diarrhea and vomiting can occur. You may also see the roundworms in your dog’s vomit or stool.

Remember that both vomiting and diarrhea are also signs of many other common health issues in adult dogs; to be sure, check with your veterinarian if the symptoms persist.

What Are the Signs of Roundworm in Puppies?

Vomiting and Diarrhea

Puppies are at much higher risk for roundworm than adult dogs, and diarrhea is a common sign. Puppies may sometimes vomit up whole worms or pass them in their stool.

Poor Growth and Poor Condition

Puppies with roundworms often show signs of poor growth and may:

  • Be small for their age
  • Have a potbelly
  • Have a dull coat in poor condition


In very young puppies, roundworm larvae migrate through the lungs, which can lead to pneumonia and a cough. As with all the above symptoms, it’s always worth consulting your vet if you spot any of these warning signs — they can indicate other health issues, too.

Can People Get Roundworm from Dogs and Puppies?

Yes, humans can pick up roundworm by accidentally ingesting eggs from soil or other infected surfaces. While many roundworm infections in humans are not especially concerning — healthy adults may not notice any symptoms — children are most at risk for more severe cases, particularly those who often play in dirt. Learn more about intestinal worms your pet could pass to your family with our handy guide.

How to Treat and Help Prevent Roundworm

Roundworm infection in dogs is very common, and treatment is easy to give and typically free of complications if caught early. Deworming treatments can kill this common parasite. Puppies should be given roundworm treatment according to the product label; make sure the product you are using is suitable for very young puppies.

Deworming adult dogs is essential for killing any roundworms and other common intestinal parasites your pet may pick up. Good hygiene is important, too: wash your hands after playing with your dog and before mealtimes, and clean your dog’s bedding, blankets and food bowls regularly. Always pick up your dog’s waste to help prevent the spread of worms, too.

With a few proactive measures and a quick response to any signs of worms, your dog or puppy can get back to feeling their best.

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Date of review March 2022

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