Key points

• Dogs get worms from contaminated soil, infected fleas, raw meat, and even their mothers.

• Five main types of parasites affect dogs: hookworms, roundworms, whipworms, tapeworms, and heartworms.

• Year-round prevention and routine fecal testing are the best defense.

Sigh. "What's in your mouth?" The answer is sometimes disgusting, occasionally alarming, and can even be the reason a dog ends up with worms. Thankfully, worms are usually far less mysterious and far more treatable than they first seem.

So, how do dogs get worms? Dogs pick up intestinal parasites from contaminated soil, infected fleas, raw prey, and even from their own mothers during birth or nursing. Some parasites, like heartworms, arrive via a single mosquito bite.

It's not the part of dog ownership anyone puts on Instagram, but understanding what types of worms in dog poop you might encounter – and what to do about them – is one of the most practical things you can learn as a dog parent. Most worm infections are far less scary once you know the basics.

A little knowledge goes a long way when it comes to parasites, especially when it helps you separate a routine problem from a real emergency. It helps to know what types of parasites your dog could face, how they're spread, the warning signs, and exactly what steps to take, so you never have to panic-scroll at 11 p.m. again.

What are worms in dogs?

Worms in dogs are internal parasites that live in the intestines, heart, or lungs and feed on your dog's blood, nutrients, or tissue. They're incredibly common. Intestinal parasites are so common that, in one nationwide survey, nearly 36% of dogs carried at least one major intestinal worm parasite.

The most frequent types include hookworms, roundworms, whipworms, tapeworms, and heartworms. Each type has a different lifecycle, transmission route, and impact on your dog's health. Some are microscopic and can only be detected through fecal testing, while others, like tapeworm segments, may be visible in your dog's stool.

Puppies are especially vulnerable. Many are born with roundworms passed from their mother in utero or through nursing. Their developing immune systems can't fight off parasites as effectively, which is why early deworming is so important.

Adult dogs are at risk too. Any dog that goes outside, visits dog parks, or interacts with other animals can be exposed. Even dogs who are primarily indoors aren't completely safe as fleas and mosquitoes can carry parasites right into your home.

Here's the thing that surprises most parents: a dog can carry worms and look perfectly healthy. That's why routine testing matters even when nothing seems wrong.

Types of worms in dogs

Dogs can be infected by several types of intestinal parasites, one cardiovascular parasite, and one common protozoan.

Hookworms

Hookworms are small, thin parasites that attach to the lining of your dog's intestinal wall and feed on blood. They're one of the most dangerous intestinal parasites, particularly for puppies and small dogs.

How dogs get hookworms: Dogs become infected by swallowing hookworm larvae in contaminated soil or water, or through skin penetration – larvae can burrow through your dog's paw pads during walks. According to Cornell University's College of Veterinary Medicine, hookworm infection is especially common in warm, humid climates where larvae thrive in soil.

Puppies can also get hookworms from their mother's milk.

Symptoms: Hookworms cause bloody or dark, tarry stools, diarrhea, weight loss, pale gums (a sign of anemia), and lethargy. In severe cases, especially in puppies, hookworm-related blood loss can be life-threatening.

Treatment: Vets typically prescribe a dewormer for dogs containing pyrantel pamoate or fenbendazole. Multiple doses are usually needed because dewormers kill adult worms but not always larvae. Your vet will recommend follow-up fecal tests to confirm the infection has cleared.

Hookworms in dogs can cause rapid, dangerous blood loss in young or small dogs. If you notice blood in your dog's stool or signs of anemia, contact your vet right away. 

Roundworms

Roundworms in dogs are the most common canine intestinal parasites. They're long, spaghetti-like worms that live in the intestines and absorb nutrients from your dog's food.

How dogs get roundworms: Roundworm larvae can be transmitted from mother to puppy across the placenta before birth or through milk during nursing.

Dogs of any age can also become infected by swallowing roundworm eggs in contaminated soil or eating infected rodents. Coming into contact with another dog's feces is another common route.

Symptoms: A pot-bellied appearance (especially in puppies), vomiting, diarrhea, dull coat, and visible worms in stool or vomit. Heavy infections can cause intestinal blockages in puppies.

Treatment: A dewormer for puppies and dogs – typically pyrantel pamoate or fenbendazole – is the standard treatment. Puppies should be dewormed starting at two weeks of age, with repeated doses every two weeks until they're about eight weeks old.

Because nearly all puppies are born with or quickly exposed to roundworms, early deworming is essential.

Whipworms

Whipworms are thread-like parasites that live in the lower part of a dog's intestinal tract. They're named for their distinctive whip-like shape – thin at the head and thicker at the tail.

How dogs get whipworms: Dogs become infected by swallowing whipworm eggs from contaminated soil. The eggs are extremely hardy and can survive in the environment for years, according to Cornell University's College of Veterinary Medicine. This makes reinfection a persistent risk, especially in areas where infected dogs have previously defecated.

Symptoms: Whipworm infections can be tricky to detect. Light infections may produce no symptoms at all. Heavier infections can cause watery or bloody diarrhea, weight loss, and general poor condition. Unlike other worms, whipworm eggs are shed intermittently, making them harder to catch on a single fecal test.

Treatment: Fenbendazole is the most commonly prescribed dewormer for whipworms. Treatment typically requires multiple doses over several weeks, with follow-up fecal testing. Because eggs persist in the environment, your vet may recommend periodic retreatment.

Tapeworms

Tapeworms are flat, segmented parasites that attach to the wall of your dog's small intestine. They can grow quite long but typically cause less severe illness than hookworms or heavy roundworm infections.

How dogs get tapeworms: The most common route is by swallowing an infected flea during grooming. Fleas carry tapeworm larvae, so a flea problem and a tapeworm problem often go hand in hand. Dogs can also get tapeworms by eating infected rodents or raw meat.

Symptoms: You might notice small, rice-like segments in your dog's stool, around their rear end, or on their bedding. These are dried tapeworm segments. Other signs include scooting, mild weight loss, and a dull coat. Tapeworms aren't always detected on standard fecal tests because they shed segments rather than individual eggs.

Treatment: Praziquantel is the go-to dewormer for tapeworms. It's effective with a single dose in most cases. However, treatment won't prevent reinfection – you'll also need to address the flea problem. Without flea control, tapeworm in dogs will keep coming back.

If your dog has tapeworms, check for fleas too. Treating one without the other leaves the cycle intact.

Heartworms

Heartworms are a different category entirely. Unlike intestinal parasites, heartworms live in the heart, lungs, and associated blood vessels. Heartworm disease is serious and potentially fatal if untreated.

How dogs get heartworms: Heartworms are transmitted exclusively through mosquito bites. When an infected mosquito bites your dog, it deposits microscopic heartworm larvae into the skin. Over about six months, these larvae migrate to the heart and lungs, where they mature into adult worms up to 12 inches long.

Symptoms: Early-stage heartworm disease may show no symptoms. As the disease progresses, dogs may develop a persistent cough, exercise intolerance, fatigue, decreased appetite, and weight loss. Advanced cases can lead to heart failure.

Treatment: Treating heartworm in dogs is expensive and complicated. It also requires months of strict activity restriction. Prevention is far safer and more cost-effective than treatment. Year-round heartworm preventives are the standard of care and are available as monthly chewables or injectable options.

Heartworm disease is preventable but not easily reversible. Talk to your vet about starting your dog on a year-round heartworm preventive.

Giardia

No, Giardia isn't technically a worm – it's a microscopic protozoan parasite, but it deserves a mention alongside worms because it causes many of the same digestive symptoms and is one of the most common intestinal parasites in dogs. The CDC estimates Giardia infects up to 45% of kennel-housed dogs in the United States, making it more prevalent than most worm species.

How dogs get Giardia: Dogs become infected by swallowing Giardia cysts from contaminated water, soil, or surfaces. Puddles, streams, shared water bowls, and dog park grounds are common sources. Unlike worm eggs, Giardia cysts are immediately infectious once shed, so a dog can pass the parasite to others right away.

Symptoms: Soft, greasy-looking diarrhea is the hallmark sign. Stools may be pale or unusually foul-smelling. Some dogs also experience gas, nausea, and weight loss. Mild infections can be intermittent. Your dog may seem fine one day and have loose stools the next.

Treatment: Vets typically prescribe metronidazole or fenbendazole. A combination of both is sometimes used for stubborn infections. Giardia cysts can reinfect your dog from the environment. Your vet may recommend a bath on the last day of treatment to remove any cysts from the coat. Cleaning and disinfecting living areas helps prevent reinfection.

Why it matters: Giardia is easy to miss because symptoms come and go. It's also zoonotic, meaning that humans can catch it from the same contaminated water sources. If your dog has recurring loose stools that don't respond to a bland diet, ask your vet to test specifically for Giardia.

Dog Worm types at a glance

Worm type	How dogs get it	Key symptoms	Common treatment
Hookworms	Contaminated soil, skin penetration, mother's milk	Bloody stool, anemia, weight loss	Pyrantel pamoate, fenbendazole
Roundworms	Mother (in utero/nursing), contaminated soil, infected prey	Pot belly, vomiting, visible worms in stool	Pyrantel pamoate, fenbendazole
Whipworms	Contaminated soil	Watery/bloody diarrhea, weight loss	Fenbendazole
Tapeworms	Infected fleas, raw meat, infected rodents	Rice-like segments in stool, scooting	Praziquantel
Heartworms	Mosquito bites	Cough, exercise intolerance, fatigue	Complex multi-month protocol; prevention preferred

How do dogs get worms?

Dogs get worms through a handful of common transmission routes, many of which are part of everyday life. Understanding these pathways helps you reduce your dog's risk.

Contaminated soil and environment: This is one of the biggest sources of intestinal parasites. Hookworm, roundworm, and whipworm eggs or larvae can survive in soil for weeks to years. Your dog can pick them up by walking on, digging in, or sniffing contaminated ground, including dog parks, backyards, and hiking trails.

Fleas: Fleas are the primary carriers of tapeworm larvae. When your dog swallows an infected flea while grooming, the tapeworm larvae are released in the intestines. Flea control is a critical part of worm prevention.

Infected prey and raw meat: Dogs that hunt rodents, rabbits, or other small animals can ingest tapeworm or roundworm larvae. Raw or undercooked meat can carry the same risk.

Mosquitoes: Heartworms are spread exclusively through mosquito bites. Any dog in a mosquito-prone area is at risk – even indoor dogs, since mosquitoes can enter homes.

Contact with infected animals or feces: Sniffing or stepping in another dog's feces, sharing contaminated water bowls, or socializing at a dog park can expose your pup to parasite eggs and cysts.

Mother-to-puppy transmission: This is how most puppies get worms. Roundworm larvae can cross the placenta before birth and pass through milk during nursing. Hookworm larvae can also be transmitted through nursing. This is why vets recommend deworming puppies starting at just two weeks old.

Identifying types of worms in dog poop

One of the first things parents notice is something unusual in their dog's stool. Different parasites leave different calling cards, and knowing what to look for can help you give your vet useful information.

Roundworms are the easiest to spot. They look like white or light brown spaghetti strands, often several inches long. You might see them in stool or vomit.

Tapeworm segments appear as small, flat, rice-like specks near your dog's rear end, on their bedding, or in fresh stool. They may wiggle when fresh and dry out to a yellowish color.

Hookworms and whipworms are too small to see with the naked eye. Your vet identifies them through a fecal float test that detects their eggs under a microscope.

Heartworms don't appear in stool at all. They live in the cardiovascular system and are detected through blood testing.

If you see anything unusual in your dog's poop – worms, segments, mucus, or blood – save a sample and call your vet. A photo can also help your vet narrow things down before the appointment.

Signs and symptoms of worms in dogs

Knowing the signs of worms in dogs helps you catch infections early. Symptoms vary depending on the type and severity of the infection, but common warning signs include:

• Diarrhea (sometimes with blood or mucus)

• Visible worms or worm segments in stool or around the rear end

• Vomiting (sometimes with visible worms)

• Pot-bellied appearance, especially in puppies

• Weight loss despite a normal appetite

• Dull, dry coat

• Scooting or dragging rear on the ground

• Lethargy and weakness

• Pale gums (a sign of anemia from hookworms)

• Coughing (may indicate heartworms or migrating larvae)

Some dogs, especially adults with light infections, may show no symptoms at all. That's why routine fecal testing matters even when your dog seems perfectly healthy.

When to call your vet: If you notice signs of worms in your dog's poop, unexplained weight loss, bloody stool, or lethargy, schedule a vet appointment. For puppies with diarrhea or vomiting, don't wait, young dogs can become dehydrated and anemic quickly.

What to do if you think your dog has worms

If you suspect your dog has worms, take these steps:

1. Collect a stool sample. Scoop a fresh sample into a clean container or bag. Your vet needs this for testing.

   
   

2. Schedule a vet appointment. Call your vet and let them know what you've observed: visible worms, diarrhea, or other symptoms.

   
   

3. Don't self-treat. Over-the-counter dewormers may not target the right worm type. Your vet will prescribe the correct medication.

   
   

4. Act fast for puppies. Young dogs can become dehydrated and anemic quickly. If your puppy has diarrhea, vomiting, or pale gums, don't wait – call your vet the same day.

   
   

5. Isolate if possible. Keep your infected dog's waste separate from areas where other pets or children play.

How are worms in dogs diagnosed?

Your vet will typically diagnose worms through a fecal examination. This involves analyzing a stool sample under a microscope to identify parasite eggs or larvae. Routine fecal testing is a smart move for any dog, even if they seem healthy. It's a quick, routine test – and one of the most effective ways to catch infections early.

Some worms are harder to detect than others. Whipworm eggs are shed intermittently, so a single negative test doesn't always rule out infection. Tapeworms often aren't found on standard fecal floats because they shed segments rather than individual eggs.

Your vet may recommend repeat testing if symptoms persist.

Heartworms are diagnosed with a blood test, not a fecal test. Annual heartworm testing is recommended for all dogs, even those on preventives.

How to treat worms in dogs

The good news: most intestinal worm infections are highly treatable with prescription dewormers from your vet. The specific dewormer for dogs depends on the type of worm involved.

Common deworming medications include:

• Pyrantel pamoate – effective against roundworms and hookworms. Often the first dewormer puppies receive.

• Fenbendazole – a broad-spectrum dewormer that treats roundworms, hookworms, whipworms, and some tapeworm species. Usually given over several consecutive days.

• Praziquantel – the standard treatment for tapeworms. Typically effective in a single dose.

What to expect during treatment:

• Your vet will prescribe a dewormer based on fecal test results or suspected worm type.

• Multiple rounds of treatment are common because most dewormers kill adult worms but not larvae or eggs.

• Follow-up fecal tests confirm the infection has cleared.

• You may see dead worms in your dog's stool after treatment – this is normal.

For puppies: Deworming should begin at two weeks of age, with repeated doses every two to three weeks. Your vet will set an appropriate schedule based on your puppy's needs.

For heartworms: Treatment is more complex. It involves injectable medications to kill adult worms and months of strict exercise restriction with ongoing monitoring. Prevention is always safer and more affordable than treating an active infection.

Important: Over-the-counter dewormers may not target the right type of worm. Always work with your vet to ensure your dog gets the right treatment.

How to prevent worms in dogs

Prevention is the most effective strategy against worms. A combination of regular vet care and consistent parasite preventives can drastically reduce your dog's risk.

Year-round parasite preventives: Monthly heartworm preventives also protect against several types of intestinal parasites, including roundworms and hookworms. Your vet can recommend the right product for your dog's needs.

Routine fecal testing: Annual fecal exams catch infections before they become serious.

Flea control: Since fleas transmit tapeworms, consistent flea prevention is also worm prevention. Year-round flea and tick products are the gold standard.

Practical habits that help:

• Pick up your dog's poop promptly, both in your yard and on walks

• Avoid letting your dog eat raw or undercooked meat

• Discourage hunting and scavenging behavior

• Wash your hands after handling your dog's waste

• Keep your dog's living areas clean and dry

Puppy-specific prevention: Start deworming at two weeks of age per your vet's guidance. Stick to the recommended preventive care schedule for vaccines, deworming, and fecal tests through the first year.

Don't skip the vet visits: Even dogs on preventives should have annual wellness exams with fecal screening. No preventive is 100% effective, and early detection makes treatment simpler and more successful.

What Does It Cost to Treat Worms in Dogs?

The cost of treating worms in dogs depends on the type of parasite involved and how early it's detected. A straightforward intestinal worm infection may cost as little as $50-$300 for an exam, fecal test, and prescription dewormer. More severe infections may require follow-up testing, additional medications, or supportive care.

Heartworm disease is typically much more expensive. Treatment often costs $600-$3,000 or more due to the medications, monitoring, repeat visits, and activity restrictions required throughout treatment.

Prevention is almost always less expensive than treating an active infection.

For preventive care, Pumpkin Wellness Club reimburses routine services like fecal tests, which can help identify infections before they become more serious. Wellness Club members can also reach out to PawSupport, a 24/7 pet health helpline, for guidance when they're unsure whether symptoms like diarrhea, vomiting, or unusual stool need veterinary care.

Can humans get worms from dogs?

Yes, some types of dog worms can be transmitted to humans, a phenomenon known as zoonotic transmission. This is one of the most important reasons to keep your dog's parasite prevention current.

Hookworms are the most common zoonotic risk. Hookworm larvae in contaminated soil can penetrate human skin, causing a condition called cutaneous larva migrans, which is an itchy, red, winding rash. The CDC reports that this occurs most often from walking barefoot in areas where infected animals have defecated.

Roundworms can also infect humans, particularly children who play in contaminated soil. After the eggs are swallowed, the larvae can migrate through the body and damage organs or, in rare cases, the eyes.

Tapeworms are rarely transmitted from dogs to people. In the uncommon cases that do occur, the source is usually an infected flea rather than direct contact with the dog. While human infections are generally not serious, they can cause digestive symptoms and require treatment.

Keeping your dog worm-free isn't just about their health, it's about your family's health too.

Other worm-related risks and considerations

Worms don't exist in isolation – they often overlap with other health concerns worth knowing about.

Flea prevention is worm prevention. Because fleas transmit tapeworms, a flea problem can quickly become a worm problem too. Year-round flea and tick products protect against both.

Multi-pet households face higher risk. If one dog in your home tests positive for worms, all pets should be tested. Cats can contract many of the same parasites from the same environmental sources. Shared living spaces and yards increase exposure.

Digestive symptoms aren't always worms. Diarrhea in dogs can have many causes, from dietary changes to infections. If your dog has persistent digestive issues, a fecal test helps your vet rule parasites in or out.

How to Keep Your Dog Worm-Free

Dogs will always find ways to investigate things we'd rather they leave alone. That's part of being a dog. The good news is that most worm infections are preventable, treatable, and much less intimidating once you understand how they spread.

You can't control every puddle, patch of grass, or mystery object your dog encounters, but you can stay ahead of parasites with routine testing, preventive care, and a little awareness. The next time your dog turns up with something questionable in their mouth, you'll know a little more about what risks come with that curiosity.

Frequently asked questions

How do dogs get worms?

Dogs get worms through several common routes: swallowing parasite eggs from contaminated soil, eating infected fleas, or nursing from an infected mother. They can also pick up worms from infected prey, raw meat, or mosquito bites.

Can humans get worms from dogs?

Yes. Hookworms can penetrate human skin from contaminated soil, causing itchy rashes. Roundworm eggs, if accidentally ingested, can migrate through human tissues. Children are most at risk. Regular deworming and good hygiene significantly reduce the danger.

What are signs your dog has worms?

Common signs include diarrhea, visible worms in stool, vomiting, a pot-bellied appearance, weight loss, scooting, lethargy, and pale gums. Some dogs show no symptoms at all, which is why routine fecal testing is essential.

How do puppies get worms?

Most puppies get worms from their mother. Roundworm larvae cross the placenta before birth. Both roundworm and hookworm larvae also pass through milk during nursing. That's why vets recommend starting a dewormer at just two weeks of age.

Are dog worms contagious?

Some dog worms can spread between animals, but the route depends on the parasite. Roundworms, hookworms, and whipworms are often spread through contaminated soil or feces, while tapeworms usually require an infected flea. Heartworms cannot spread directly from one dog to another.

How often should you deworm a dog?

The right deworming schedule depends on your dog's age, lifestyle, and parasite risk. Puppies need multiple deworming treatments during their first few months of life, while adult dogs typically rely on routine fecal testing and year-round parasite prevention.