Symptoms of Worms in Dogs: How to Identify and Act on Them

Internal parasites are a persistent reality in dog ownership, and recognizing the warning signs early makes a real difference in outcomes. The most common symptoms of worms in dogs range from subtle digestive changes to visible parasites in the stool. Understanding the different types of worms in dogs helps explain why symptoms vary so much from dog to dog. The types of worms dogs get — roundworms, hookworms, tapeworms, whipworms, and heartworms — each affect different body systems and require different treatments. Knowing the sign of worms in dogs for each type avoids guesswork, and the question what kind of worms does my dog have is one your vet can answer definitively with a fecal test.

Puppies are especially vulnerable to worm infestations because they can be born with roundworms passed from their mother. Adult dogs pick up parasites from contaminated soil, water, infected prey animals, and fleas. Routine deworming and fecal testing once or twice per year is standard practice in most veterinary preventive care protocols.

Types of Worms Dogs Get and Their Symptoms

Roundworms

Roundworms are the most common internal parasite in dogs, especially in puppies. Symptoms of worms in dogs of this type include a pot-bellied appearance, vomiting (sometimes expelling actual worms), diarrhea, failure to thrive, and a dull coat. Adult roundworms are visible in vomit or feces — they look like cooked spaghetti, 2 to 4 inches long. Most puppies are born with them or acquire them through nursing.

Hookworms

Hookworms attach to the intestinal wall and feed on blood. The sign of worms in dogs from hookworms includes pale gums, weakness, bloody or tarry diarrhea, and weight loss. Puppies can die from hookworm-related anemia. These parasites enter through the skin or are ingested from contaminated ground. What kind of worms does my dog have if gums look pale and energy is very low? Hookworms are high on the list.

Tapeworms

Tapeworms are transmitted primarily through flea ingestion. The most recognizable sign of worms in dogs for this type is small rice-like segments around the anus or in fresh stool. Dogs may scoot on the floor due to anal irritation. Tapeworm infestations rarely cause serious illness in adult dogs, but active flea control is needed alongside deworming to prevent reinfestation.

Whipworms

Whipworms live in the large intestine and are harder to detect than other types of worms dogs get. Symptoms of worms in dogs from whipworms include chronic, mucus-heavy diarrhea (sometimes with blood), weight loss, and general malaise. Because whipworm egg shedding is intermittent, a single negative fecal test doesn’t rule them out. Multiple tests or a fecal antigen test may be needed.

Heartworms

Different types of worms in dogs include heartworms, transmitted by mosquitoes and living in the heart and pulmonary arteries. Early heartworm infection has no visible symptoms. As disease progresses: exercise intolerance, coughing, reduced stamina, and eventually heart failure. What kind of worms does my dog have if they’re coughing and tiring easily on walks? Heartworms must be ruled out. Annual testing is the standard, and monthly preventatives are highly effective.

Diagnosing and Treating Worms

A routine fecal flotation test identifies eggs from roundworms, hookworms, tapeworms, and whipworms. Heartworms require a blood antigen test. Treatment depends on the parasite: pyrantel pamoate and fenbendazole for roundworms and hookworms, praziquantel for tapeworms, and a veterinary-supervised protocol with melarsomine injections for heartworms. Never self-diagnose and treat — over-the-counter dewormers address only some worm types and may miss what’s actually present.

Next steps: Schedule a fecal test at your next vet visit if it’s been more than a year. If you notice visible worm segments, a scooting dog, or a puppy with a distended belly, contact your vet sooner. Keep monthly heartworm prevention current regardless of whether intestinal parasite signs are present.