Worms in Dogs: Signs, Types, and When to See Your Vet

Worms in dogs

Intestinal worms are parasites that live in a dog's digestive tract. Different types cause different signs, and some infected dogs appear healthy on the outside.

Over-the-counter dewormers may not treat every worm type effectively. A fecal test helps your veterinarian choose the right treatment and check whether reinfection or other parasites are involved.

Symptoms

Signs vary by worm type, infection severity, and your dog's age and health. Puppies and dogs with heavy burdens may show more obvious symptoms.

Some owners discover worms only when they see them in stool or around the anus. Other dogs are diagnosed during routine fecal testing at a wellness visit.

• Visible worms or worm segments in stool or around the anus
• Diarrhea, soft stool, or mucus in stool
• Vomiting or reduced appetite
• Weight loss despite normal eating
• Pot-bellied appearance in puppies
• Dull coat, lethargy, or poor growth in young dogs
• Scooting or irritation around the rear end

Common causes

Dogs often pick up worms by ingesting worm eggs or larvae from contaminated soil, feces, or prey. Puppies can also acquire certain worms from their mother before or after birth.

Fleas can transmit tapeworms when a dog swallows an infected flea. Dogs that hunt rodents or eat raw meat may have higher exposure risk.

• Ingesting worm eggs from contaminated soil or feces
• Transmission from mother to puppies
• Swallowing infected fleas (tapeworms)
• Eating prey animals or uncooked meat
• Contact with infected animals or environments

What to do now

If you see worms in your dog's stool, contact your veterinarian. Bring a fresh stool sample if your clinic requests one — it helps identify the parasite type.

Keep your dog's living area clean and dispose of stool promptly. If you have other pets, mention this to your vet because some worms can spread between animals.

• Call your veterinarian to schedule a fecal examination
• Collect a fresh stool sample if your clinic advises it
• Clean up stool promptly in your yard and on walks
• Note any vomiting, diarrhea, or appetite changes
• Tell your vet about other pets in the household

What not to do

Do not use livestock dewormers, natural remedies, or leftover pet medications without veterinary guidance. Wrong products may be ineffective or unsafe.

Do not assume one visible worm means only one type of parasite is present — dogs can carry multiple worms at once.

• Do not give deworming medication without veterinary direction
• Do not ignore worms in puppy stool — puppies can become ill quickly
• Do not rely on visual identification alone to choose treatment
• Do not skip follow-up testing if your veterinarian recommends it

When to call a vet

Contact your veterinarian if you see worms in stool, if your dog has persistent diarrhea or weight loss, or if a puppy seems unwell.

Routine fecal testing at wellness visits is also recommended — many infections are found before obvious signs appear.

• Visible worms or worm segments in stool
• Persistent diarrhea, vomiting, or appetite loss
• Weight loss or failure to thrive in puppies
• Lethargy, pale gums, or weakness
• Routine wellness visit — ask about fecal parasite screening

Diagnosis and treatment overview

Your veterinarian typically diagnoses intestinal worms through a fecal examination, sometimes repeated to catch intermittent shedding. Blood work may be recommended if your dog seems ill.

Treatment depends on the worm type identified. Your vet will prescribe an appropriate deworming protocol and may recommend follow-up testing to confirm the parasites are cleared.

Prevention

Pick up stool promptly, keep your yard clean, and follow your veterinarian's parasite prevention recommendations. Many heartworm preventives also cover some intestinal worms.

Puppies should receive deworming and fecal checks on a schedule your veterinarian recommends. Reduce flea exposure to lower tapeworm risk.