Roundworms in Dogs: Symptoms and Prevention

7 min read
7 min read

Updated - Aug 30th, 2022

Key Points

  • Roundworms are parasitic worms that attach themselves to the inside of your dog’s intestinal tract, living off of them until treated.
  • Treatment is relatively simple! Your veterinarian will prescribe deworming medication until the infection is cleared.
  • Once your dog is free of roundworms, you should start a monthly anti-parasite preventative medication to prevent future infections from parasites.

Roundworms are the most common parasitic worm infection found in dogs, so if you suspect your dog is infected, you’re certainly not alone.

Adult roundworms will grow and live in the infected dog’s stomach, attaching themselves to the intestines, and will survive off of partially digested food, multiplying until treated. This deprives the affected dog of the normal nutrients they would normally get from their food and can lead to malnutrition and other medical conditions.

Whether roundworms are passed on to your pup from their mother or picked up at the local park, there are many ways your dog could become infected. Fortunately, there are simple treatment options that can get your dog on the road to recovery in no time.


First things first – how do you know if your dog has roundworms? Though the only way to know for sure is to obtain a diagnosis from your vet, here are the main symptoms of roundworms to look out for:

  • Malnourishment: Because roundworms feed off of partially digested food in your dog’s stomach, they steal away nutrients your dog would normally receive. In turn, your pup may show signs of malnutrition, such as weight loss, weakness, stunted growth, and a weakened immune system.
  • Diarrhea and vomiting: Since roundworms survive in your dog’s intestines, they can cause irritation resulting in vomiting or diarrhea. Depending on the severity of the infection, you might visibly see the worms in your pup’s vomit or feces.
  • Pot-bellied appearance: In puppies, a tell-tale sign of a roundworm infection is a pot-bellied appearance. If left untreated, roundworms will quickly grow and reproduce causing their stomach to appear bloated.
  • Dull, thin coat: As your dog suffers from roundworms and malnutrition, their coat might appear thinner or duller. This is likely due to the lack of nutrients and stress that the infection has caused. 

It’s worth noting that there are some cases where dogs don’t show any symptoms of having roundworms. If you think something might be wrong with your pup, we always recommend taking your dog to a veterinarian to be examined. 


Roundworms are the most common parasitic worm that infects dogs. The most common time dogs are infected is when they’re a puppy, but roundworm infections can still happen to adult dogs, too.

Some common causes of roundworms in dogs include:

  • Transport host: Birds, rodents, earthworms, and other small animals can act as host bodies, transporting roundworms until a larger animal eats the host and the roundworms are able to infect their new host body.
  • Feces: Infected animals can pass on roundworm eggs through their poop. When a dog sniffs or licks infected fecal matter, they have a chance of picking up the infective eggs themselves. 
  • Environment: We all know that young puppies like to chew on just about everything. Unfortunately, when your little pup is chewing on a patch of grass, they might also be ingesting roundworm eggs. Roundworm eggs can be found in soil or plants, so it’s hard to keep your puppy away from any exposure. 
  • From their mother: Surprisingly, many puppies get roundworms from their mothers. If pregnant dogs are infected with roundworms, roundworms can be transmitted to the puppies through the placenta before birth, or through nursing as the puppies drink their mother’s milk. 

 For more information on how dogs get worms, take a look at all the different types of worms your dog could face in their lifetime.


There are two main species of roundworm, Toxocara Canis and Toxascaris Leonina. It’s important to note that the Toxocara canis, or “t. canis,” is the most common and more dangerous of the two species. It can be transmitted to humans and can cause serious illnesses if left untreated. 

In most cases, your vet will diagnose a roundworm infestation by examining a sample of your dog’s feces under a microscope and checking if there are any roundworm eggs present. In serious cases, pet owners might see live roundworms in their dogs’ feces or vomit. In this case, you should take your dog to a veterinarian as soon as possible. 

If roundworm eggs are present, your vet will then take steps to determine what type of roundworm your dog is infected with and the best treatment options. Your vet will do this to determine if there is any risk of transmissible infection.


It can be heartbreaking to learn that your furry friend has been infected with roundworms. As frightening as it sounds, don’t panic! Treatment for roundworms is an easy and relatively straightforward process.

Your vet will treat your pup’s roundworm infection with a dewormer anti-parasite medication. Most anti-parasite medications will only kill the adult worms in your dog, so your vet may recommend a couple of rounds of anti-parasite medication to ensure your dog is fully cleared of the infection.  

In serious cases, your vet may deem hospitalization necessary to give them the supportive care they need until they’re in a more stable condition.

Once your dog has taken their deworming medication, your vet will offer options for a monthly preventative anti-parasite medication which will help prevent roundworm, heartworm, hookworms, and other parasites from infecting your dog in the future.

Recovery and care

 Once your dog is diagnosed with roundworms and has started the deworming treatment, there isn’t much you need to do other than make sure they’re eating and drinking enough. The medication will work its magic – and after a couple of cycles of the dewormer, your dog should make a full recovery.

While there isn’t much more you need to do for your dog, it’s important that you take special precautions when handling your dog or their feces. Make sure you and members of your household understand the situation and are washing your hands thoroughly to prevent any chance of the infection spreading.


 Luckily, there is a number of amazing anti-parasite medications you can give your dog.

These medications can vary, so it’s important to consult with your local veterinarian on which anti-parasite medication is best for your furry friend.  

These preventive medications will not only help protect your dog from roundworm but also help other parasites such as tapeworms, hookworms, fleas, and ticks from trying to get a free meal at the expense of your dog. 

What to expect at the vet’s office

First, a vet will check your dog’s overall health, looking for signs of malnourishment or illness that might be caused by a roundworm infection, such as a thin or dull coat or weight loss. 

Your vet might have asked for you to bring in a sample of your dog’s feces. In this case, they will examine the fecal sample under a microscope to determine if there are any signs of roundworm eggs or infective larvae.

If roundworm eggs are present, they will then prescribe deworming medication to treat the immediate infection and monthly anti-parasite preventative medication to help keep your dog happy, healthy, and parasite-free in the future.

The bottom line

The best way to know whether or not your dog has a roundworm infection is to obtain a diagnosis from your vet. They’ll be able to prescribe treatment options based on the severity of the infection and the condition your dog is in. 


Can pet insurance cover treatment for roundworms?

Pet insurance plans, like Pumpkin plans, can help you pay for expenses associated with unexpected accidents or illnesses. If your plan is effective and your dog is unexpectedly diagnosed with a roundworm infection in the future, eligible diagnostic testing may be covered.

Pet insurance providers may also offer optional wellness packages, like Pumpkin Preventive Essentials. This is not insurance, but an optional add-on that reimburses you for eligible routine care like an annual parasite screening.

How do I treat my dog’s roundworm infection?

Your vet will determine the best course of action for addressing a roundworm infection in your dog. This will depend on the severity of the infection.

Can roundworm infections be prevented?

The short answer: yes! Roundworm infections can be prevented with monthly preventative anti-parasite medication.

Did you know

  • Roundworms are the most common parasite out of all of the worms that infect dogs.
  • There are two main species of roundworm: Toxocara Canis and Toxascaris Leonina.
  • Pumpkin Dog Insurance plans cover 90% of eligible vet visits — making it easier for you to provide your pet the best possible care if accidents and illnesses arise. Fetch a quote today!
Tristan Robinson

Tristan Robinson

Tristan is a copywriter and proud dog uncle of a rambunctious Goldendoodle named Lily.
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