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Three dogs playing in a dog park

The essentials

  • Intestinal parasites are common in dogs — Your vet can help you determine which type of parasite your pup is dealing with, provide treatment, and determine if they’re zoonotic.
  • Treatments range from pills to injections — The duration of your dog’s treatment will depend on the severity of their infection and how well they respond to medication.
  • Prevention is key — Easy-to-follow measures help keep intestinal parasites at bay so they don’t become a problem to begin with.

Believe it or not, many organisms live rent-free inside your dog. Some provide health benefits, such as helping to break down food or regulate chemical balances. Others, like intestinal parasites, can cause serious health problems.

The most common intestinal parasites are roundworms, tapeworms, hookworms, whipworms, coccidia, and giardia. These live off and survive at the expense of their hosts, either by stealing their food or feeding on them directly.

Signs your pup has an intestinal parasite

Most symptoms of intestinal parasites in dogs are fairly easy to identify. Some of the most common symptoms include

Puppies can pick up intestinal parasites shortly after they are born as worms can be passed through the mother’s milk. They can also become infected orally — for example, if a dog swallows dirt with dog or cat feces that’s been contaminated with adult worms, larvae, or eggs.

If left untreated, complications can arise, especially in puppies. Stunted growth, anemia, and intestinal blockages are some of the more serious complications that arise from infection. Severe infections can even result in death.

Diagnosing and treating intestinal parasites in dogs

Some of the most common parasites found in dogs are those that live in the intestines. For this reason, fecal and heartworm tests are both recommended as part of a dog’s annual wellness exam. Your dog’s veterinarian may also conduct a special test that allows them to determine if there are worm eggs in your dog’s stool.

Your vet may also conduct a blood test if they suspect your dog has heartworms.

Treatment plans often depend on factors such as your dog’s age, weight, reaction to treatment, type of parasite present, and the severity of their infection. Some dogs react better to certain forms of treatment than others, but common options include oral medicines, injections, and topical treatments.

Treating intestinal parasites in dogs

Always consult your vet for treatment if you notice any of the symptoms listed above. Your vet will prescribe safe and effective drugs to kill any parasites your dog has. Below are some of the most common types of parasites and treatments your vet may issue.

Type of parasite Common Treatment Drugs Form
Roundworms fenbendazole, milbemycin oxime, moxidectin, piperazine, pyrantel Oral, topical
Hookworms fenbendazole, moxidectin, pyrantel, milbemycin oxime Oral
Tapeworms praziquantel Oral, injection, topical
Whipworms febantel, fenbendazole, milbemycin oxime, moxidectin, oxantel Oral, topical
Coccidia sulfadimethoxine Oral
Giardia fenbendazole (sometimes combined with metronidazole) Oral

👉 Do not attempt home remedies for intestinal parasites, as these will only exacerbate symptoms. Intestinal parasites are stubborn organisms that only specific drugs can kill.

Common intestinal parasites in dogs

A parasitic infection is a disease caused by another organism living off your dog. Dogs are at risk for a variety of different intestinal parasites. Here are some of the most common parasites dog owners should look out for in Fido.

An illustrated image showing six parasites commonly found in dogs.


These white, spaghetti-like worms can travel through a dog’s body but typically make their home in their host’s large intestinal wall.

Puppies are more likely than dogs of other ages to have a roundworm infection because they can contract it in the womb or from their mother’s milk. Adult dogs can also contract roundworms by being exposed to an infected animal’s feces or vomit, or by eating another animal with roundworms.


As their name implies, hookworms “hook” themselves to the interior lining of a canine’s intestines. There, they feed on the dog’s blood and lay eggs that get passed into the digestive tract and out of the body. The resulting larvae then embed themselves in the soil and wait to hitch a ride on another dog’s paws, where they penetrate the skin or are ingested.

According to the Companion Animal Parasite Council (CAPC), young puppies are particularly vulnerable to hookworms. The bloodsucking worms can cause blood loss in pups, which can stunt their growth.


These are gastrointestinal parasites that attach themselves to the inner lining of the cecum and large intestine at the point where the large and small intestines meet. Some dogs with whipworm don’t display symptoms, making them difficult to diagnose. They’re also so tiny that it’s difficult to spot them in stool.


Tapeworms get their namesake from their flat shape and segmented anatomy. According to the CAPC, each tapeworm segment contains reproductive organs, segments of which break off as dogs pass waste.

The small segments are usually visible to the naked eye in the feces and may resemble small white seeds or individual grains of rice. Tapeworms are most commonly spread by ingestion of infected fleas.


Though heartworms aren’t an internal parasite, they’re ubiquitous enough to mention. Heartworms and heartworm larvae live in the hearts, lungs, and associated blood vessels of their hosts and can grow up to 16 inches long.

Testing and treating heartworms is a complex process and can require additional diagnostics such as chest X-rays, echocardiography, electrocardiograms, and additional blood work. Not only is testing time intensive but it can be costly, ranging from $75 to $1,000 per test. Treatment plans can also become costly, ranging from $50-$1,500 per treatment.

Contact your vet if your dog experiences symptoms like fatigue, shortness of breath, and coughing, which are all signs of heartworm. If left untreated in dogs, this type of parasitic infection can lead to heartworm disease and be fatal. Therefore it is critical to keep your dog on year-round heartworm prevention.


Unlike the aforementioned worm parasites, coccidia are single-celled organisms. But like their worm counterparts, this parasite can enter your dog’s body when they lick dirt or consume feces. Coccidia infestations occur in a dog’s intestines but are generally not very severe.

Some dogs have few symptoms other than diarrhea. However, for puppies or vulnerable adult dogs , infection from coccidia (coccidiosis) may cause severe watery diarrhea, dehydration, abdominal distress, vomiting, and in severe cases, death.


Giardia is another single-celled infectious organism. They enter their host’s body when that animal consumes contaminated water or fecal matter. They have two forms: a “feeding” form and a cyst form, the latter of which protects them from the elements when they’re outside their host.

Intestinal flukes

While not as common as other intestinal parasites, dogs can be exposed to these small, oval-shaped organisms . One common way this can happen is by eating raw or improperly prepared fish. They travel through their host’s body and settle in the small intestine, where they can cause intestinal damage, weight loss, vomiting, and diarrhea.

How do dogs get intestinal parasites?

Intestinal parasites have many ways in which they try to infect your pup. Keep an eye out for the following to minimize your dog’s chance of exposure.

  • The food they eat.  One of the best ways for intestinal parasites to enter the body is through raw food. Steer clear of raw food diets, make sure your pup has clean dishes and bowls to eat out of, and keep their food far away from fecal waste.
  • Interacting with other dogs. We love it when our pups get along with other dogs. And so do parasites! Parasites can easily transfer from one dog to another, so make sure everyone has been dewormed recently.
  • Born with them. Some intestinal parasites in pregnant dogs can travel from the intestines to the womb. These parasites then transfer to still-developing puppies in utero. Parasites can be transferred to puppies via their mother’s milk.
  • Other pests and animals. Infected fleas, ticks, rodents, and other animals can also serve as intermediary hosts to parasites. Parasites can break free from their initial hosts and make their way to the intestines of dogs who ingest infected fleas or ticks. Additionally, if your dog walks on or ingests infected fecal matter they may pick up parasites. Heartworms are also spread by the bite of an infected mosquito.

Places where your pup is most at risk

Anywhere your pup comes into contact with other dogs poses a risk. Communal settings tend to increase a pup’s chance of contracting a whole host of diseases, including parvo, distemper, flea-borne illnesses, and more. That said, a few of the most common places your pup might pick up an intestinal parasite include:

  • Animal shelters. A recent study revealed that dogs in animal shelters are far more likely to have an intestinal parasite than dogs that live in private homes. If you just picked up a new pet from your local shelter, ask your vet to run a fecal test to rule out any parasites.
  • Doggie daycare and boarding facilities. Dogs can easily pick up parasites while socializing with an infected dog. When starting your dog at a new daycare always check to see if they have a policy around parasite prevention like rules against sending your pup to daycare if they’re experiencing diarrhea.
  • Competitions or training classes. Unfortunately, pups can pick up more than just new skills at training classes and competitions. Stay up to date on your pup’s monthly heartworm treatments and keep a close eye on your pup when they’re around other dogs.
  • The dog park. These are major contributors to the spread of parasites since dogs at these parks drink from the same water dishes and play on the same fecal-ridden soil. A 2019 study found that 85% of the parks they sampled had at least one infected dog.

Prevention is the best medicine

While treatment for intestinal parasites is effective, no dog parent wants to worry about their pup experiencing discomfort or getting sick. Fortunately, with a little care and maintenance, most intestinal parasites can be stopped before they have a chance to harm your pet. Consider the following prevention tips:

Keep up with regular exams — Bring your dog to the vet for regular exams. Once or twice a year, your vet may want to collect stool samples. This is a normal process and helps to identify any parasites that could be in your dog’s digestive system.

Use a broad spectrum preventative product year-round — Year-round broad spectrum controls are an essential part of preventative veterinary care. These are designed to fight against heartworm, intestinal parasites, other zoonotic parasites, fleas, and ticks.

Clean up after your pet — Cleaning up after your dog is an essential step when it comes to preventing the spread of parasites in feces. Always keep your dog’s feeding, drinking, sleeping, and play areas clean and away from fecal matter.

Maintain good hygiene — Similarly, keeping your dog properly cleaned and groomed will help to eliminate parasites that linger on their paws, fur, mouth, or around their anus. In addition to regular baths, use pet-friendly cleaning wipes after visiting the dog park or other social places.

Know what’s near you — Dogs are keen on their surroundings, and you should be, too. Knowing which parasites are in your geographic region can help keep you informed. CAPC has a useful parasite map that you can use to identify common parasites where you live.

Avoid raw food diets — While raw food diets for dogs are trending, the American Veterinary Medical Association opposes feeding your dog raw food because of the risk of exposure to dangerous bacteria, parasites, and other microorganisms that can live in raw food. If you choose to feed your dog fresh, non-kibble food, be sure to cook it first.

Internal parasites are more common in dogs than you might realize. Fortunately, the likelihood of your dog picking one up can be reduced with proper preventative care and regular vet visits. If you suspect your dog has picked up internal or external parasites, be sure to get them seen by a vet — the sooner the better!

Frequently asked questions

What does dog poop look like with parasites?

Not all paraseites are visible to the naked eye. However, the most common intestinal worms that can be seen in a dog’s poop are hookworms, whipworms, roundworms, and tapeworms.

  • Hookworms are thin with hook-like mouth parts
  • Whipworms look like tiny pieces of thread that are enlarged on one end
  • Roundworms look like spaghetti and may be several inches long
  • Tapeworms look like grains of rice, around your dog’s anus or on their poop.

Are intestinal parasites in dogs contagious to humans?

Yes. Some intestinal parasites are considered zoonotic, which means they can be passed from dogs to humans. Roundworms, hookworms , giardia, and spirochetes are all parasites to be cautious of as they can be transferred to adults and children.

What are the symptoms of parasites in dogs?

Parasites in dogs can cause a multitude of symptoms. Intestinal parasites can cause loose stool, bloody diarrhea, weight loss, the inability to put on weight, stunted growth, dull fur, malnutrition, and more.

How do you get rid of intestinal parasites in dogs?

Intestinal parasites can be treated with veterinarian-prescribed drugs. The type, form, and dosage depend on the severity of your dog’s infection, as well as other factors like weight and age.

What are the most common intestinal parasites in dogs?

The most common intestinal parasites in dogs are roundworms, tapeworms, whipworms, hookworms, and single-celled protozoa such as coccidia and giardia.

What do parasites look like?

In their adult form, many parasitic worms look like thin spaghetti noodles and are often white or pale to light tan in color. In the larval stage, they are much smaller and not dissimilar in size to a seed or grain of rice. Single-celled parasites such as coccidia or giardia can’t be seen without special equipment, such as a microscope.

Do parasites in dogs go away on their own?

Some intestinal parasites are asymptomatic at first but can result in more severe symptoms over time. And even if symptoms appear to pass, many parasites can live dormant as cysts in your dog’s tissue for months or even years. Almost all parasitic infections in dogs require effective treatment from a vet.

What medicines kill parasites in dogs?

Many types of medications can kill intestinal parasites in dogs. Fenbendazole, moxidectin, and milbemycin oxime are a few common prescription options.