Roundworms in Dogs: Symptoms, Causes, and Treatment

Roundworms in dogs are very common in all ages and breeds—but what are they, and how do you get rid of them? Let’s look at everything you need to know, including what roundworms in dog poop look like and when to call your vet. 

What Are Roundworms in Dogs?

Roundworms in dogs are internal parasites that live inside the digestive tract of your pup, where they grow from eggs into immature worms (larvae) into adult worms. These worms can cause upset stomach, diarrhea, an unthrifty coat and a pot-bellied appearance. Roundworm larvae may also migrate to the lungs, which causes a dog to cough. 

Tell your vet right away if you see any worms in your dog’s poop, so your vet can figure out the type of worm and how to treat it. Sometimes, affected pups will vomit and have a worm in their vomit. If this happens to your dog, be sure to take a photo of the worm to show your vet. 

What Do Roundworms Look Like?

When found in the stool or vomit, roundworms look like 3- to 6-inch-long pieces of cream-colored spaghetti.   

Even when a dog has them, it’s not uncommon for pet parents to not see any worms at all. Many times, the live worms are living in the GI tract and only their microscopic eggs are being passed in the stool. Just because you don’t see any worms in your dog’s feces, doesn’t mean that they don’t have them. 

Roundworm Symptoms in Dogs

Dogs infected with roundworms may show no signs at all while still actively shedding roundworm eggs into the environment: your home and yard.  

Symptoms of roundworms in dogs may vary from mild signs to severe illness:    

• Diarrhea or soft stool; you may see a roundworm in the stool  

• Vomiting; you may see a roundworm in the vomit  

• Pot-bellied (distended) abdomen   

• Thin body condition  

• Weight loss   

• General unhealthy appearance, including dull hair coat   

• Coughing or trouble breathing if roundworms migrate to the lungs  

Heavy infections in young puppies can be fatal. 

How Do Dogs Get Roundworms?

Most puppies are infected with roundworms that are passed from the mother before birth.   

Puppies are also infected through nursing from their mother, since tiny worm larvae are in their mother’s milk. Studies have shown that virtually all puppies are born infected with roundworms.  

If you are caring for a nursing mama dog or pregnant dog, ask your vet about deworming her to treat her existing worms and prevent spreading them to her puppies.  

Roundworm infections happen when dogs eat worm eggs. This happens when a dog licks their fur and swallows the worm egg after being in a contaminated environment (like dog parks, sandboxes, gardens, play areas, shelters, or boarding facilities), or when they eat an animal infected with the worm or its eggs. 

How Do Veterinarians Diagnose Roundworms in Dogs?

To diagnose roundworms in dogs, a veterinarian will: 

• Perform a physical exam 

• Take a fresh stool sample for a fecal analysis. You can bring a poop sample from home, or your vet can get a sample during a physical examination of your dog.  If you collect a stool sample at home, don’t freeze it. Freezing the stool sample can damage the eggs and lead to false negative results. 

Even if you can see worms in your dog’s stool and have a general idea of what type of worm your dog is infected with, your veterinarian will need to do a fecal exam to ensure the worm is correctly identified.  

Your vet will also check for eggs of any other worms, since it’s common for a dog to have several different types of worms at one time. 

Roundworm Treatment for Dogs

Roundworm treatment for dogs includes deworming medication prescribed by your veterinarian, given on a strict schedule for a certain time—typically several weeks.  

Deworming medication options include: 

• Drontal Plus 

• Nemex 

• Panacur 

• Virbantel 

• Safe-Guard 

Always follow the directions provided by your veterinarian and schedule follow-up visits for your pet. 

Your dog’s stool will need to be retested to ensure treatment is working.  

Depending on their health status, dogs with lower numbers (milder infections) of roundworms can recover within a few weeks.  

If your dog has more severe symptoms, your vet may also recommend:  

• A veterinary diet, such as Hill’s GI Biome  

• A gastrointestinal probiotic, such as FortiFlora or Proviable  

• Hospitalization and supportive care  

• Fluid therapy  

Emergency surgery may be needed to remove a large amount of worms if your dog has an intestinal blockage.  

Prevention of Roundworms in Dogs

The best prevention for roundworms in dogs includes:   

• Giving your dog once-a-month parasite prevention (such as Credelio Quattro) year-round for life.   

• Routine GI parasite deworming. Puppies should receive deworming medication starting at 2 weeks of age and every two weeks thereafter until they are started on once-a-month parasite prevention.  

• Stool testing four times a year for puppies and newly adopted dogs, and twice a year for adult dogs.  

• Regular wellness visits with your veterinarian.   

• Picking up your dog’s stool right away from your yard every day.   

• Protecting sandboxes, garden areas, and playgrounds from stool contamination.  

• Using good hygiene (especially for children). Wash your hands after handling your dog or their poop, and always before meals.  

Ask your vet about giving one of these parasite preventives year-round:  

• Credelio Quattro  

• NexGard Plus  

• Simparica Trio  

• Trifexis  

• Sentinel Spectrum  

• Advantage Multi  

• Heartgard Plus  

• Interceptor Plus  

Roundworms are very common in puppies and young, growing dogs. Fortunately, they are readily treated with good veterinary care.  

Roundworms are zoonotic, meaning that they can be spread from dogs to people. Regular deworming and monthly prevention products are essential for keeping both your dog and your human family safe and parasite-free.