Roundworms in Dogs: What They Are and What To Do If You Find Worms in Your Dog’s Poop

Worms in dog poop, or gastrointestinal (GI) parasites, are very common in all ages and breeds of dogs, from young puppies to adults and senior dogs.

The most common GI parasite in dogs is roundworms, even among dogs who are well cared for. Any dog, indoor or outdoor, may be infected with roundworms, but young puppies are the most vulnerable. 

Roundworms in dogs can also cause disease in people, especially children.  

This is why keeping your dog on once-a-month parasite control year-round is very important to protect your dog and your family. 

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 cause upset stomach. Roundworm larvae may also migrate to the lungs, which causes a dog to cough.

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

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. Bring a fresh stool sample and even a worm (or a photo of the worm) to your vet for analysis.  

Roundworms in dogs are typically not a medical emergency but can become one if your pup shows severe signs of illness from being infested with several roundworms. 

If you notice that your pup is having trouble breathing, is vomiting, or is not eating, take them to your vet immediately. 

Symptoms of Roundworms 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. 

Causes of Roundworms in Dogs

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 Veterinarians Diagnose Roundworms in Dogs

To diagnose roundworms in dogs, a veterinarian will need a fresh stool sample. You can bring a poop sample from home, or your vet can get a sample during a physical examination of your dog.  

A fecal examination (called a fecal floatation test) is done to find the roundworm eggs in the stool using a microscope. This test may be done in your vet’s hospital or sent out to a laboratory.  

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. 

Treatment of Roundworms in Dogs

Roundworms in dogs are curable and generally require multiple treatments of deworming antiparasitic medication, available in various prescription and over-the-counter formulations, given on a strict schedule for a certain time, usually several weeks. 

Your vet will prescribe a deworming medication, such as Drontal Plus, Nemex, Panacur, Virbantel, or Safe-Guard. 

It’s important to carefully follow the directions provided by your vet and to schedule follow-up visits. Your dog’s stool will need to be retested to ensure treatment is working. 

Recovery and Management of Roundworms in Dogs

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 

• 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