Reviewed by Rhiannon Koehler, DMV, MPH | Products are chosen at the discretion of the company and do not represent a direct endorsement by the veterinary reviewer.
Key Takeaways
- Puppies may pass worms for several days after deworming, although the exact timing varies.
- Puppies may need repeat treatments to fully clear a worm infestation.
- Roundworms and tapeworms are easier to spot than hookworms and whipworms.
- Follow your puppy’s deworming schedule to help prevent reinfection.
- Mild diarrhea, mucus, or tiredness can occur after deworming.
- Contact your vet if severe or persistent symptoms develop.
Quick Answer: How Long After Deworming Will My Puppy Expel Worms?
Dewormer starts working within 12 to 24 hours, although the timing varies by medication. Your puppy may pass worms in their stool for several days after treatment.. Some puppies need repeat treatments to clear the infestation completely. Worms in the stool are a good sign. They confirm the medication is working.
You may see both live and dead worms. Their appearance can vary depending on the type of worm. Most dewormers kill the worms in the digestive tract first. Your puppy's body then expels them naturally. You're more likely to spot roundworms or tapeworms than hookworms or whipworms.
Deworming: What Is It and Why Is It Important?
Most worms infect a dog’s digestive system, mainly the intestines. Some species live elsewhere in the body. Heartworms take up residence in the heart and surrounding major blood vessels.
Deworming removes digestive worms with medication. Dewormers usually come as oral pills, oral liquids, or injectable products. To deworm a puppy, give your dog the exact dosage the veterinarian recommends. Using the wrong number of pills or changing the timing can cause the worms to return. Veterinarians often pair these dewormers with parasite preventatives to help address all life stages of the parasites.
Deworming is important because worms can cause gastrointestinal issues, steal nutrients from your dog, cause anemia, and infect other animals (and sometimes people). Puppies, in particular, face a higher risk of complications. Some of the symptoms include:
- Diarrhea or vomiting
- Weight loss
- Stomach pain
- Lethargy
- Dehydration
- Poor coat quality
- Swollen abdomen
- Blood in their poop
- Nutrient deficiencies
- Pale gums and weakness due to anemia
- Visible worms or worm segments in the stool, around the anus, or in bedding
Types of Worms That Affect Puppies
Four common types of worms affect a puppy’s digestive tract: roundworms, tapeworms, hookworms, and whipworms.
Roundworms
The two main types of roundworms that infect dogs are Toxocara canis (T. canis) and Toxascaris leonina. Although dogs can get either type, T. canis is much more common in puppies, and they can transmit it to humans.
Roundworms can infect puppies through their mother’s milk or while still in utero. Puppies can also become infected by consuming roundworm eggs from soil or other material contaminated with feces, or by eating an infected animal. These worms become adults in the dog’s small intestines, where they feed on nutrients from the dog’s ingesta.
People often say roundworms look like spaghetti that moves. They can grow up to six inches long. Their eggs are microscopic. Your dog could have roundworms, even if you have not seen any live worms in their stool.
Tapeworms
Puppies can contract tapeworms from infected fleas or host animals. Dipylidium caninum, which is more common, is contracted when a dog eats an infected flea, usually by grooming the flea off themselves. Taenia species, which are less common, come from the consumption of infected host animals, usually rodents.
Heavy tapeworm infestations may interfere with a puppy’s growth, cause an intestinal blockage, or irritate the area around the anus.
Tapeworms are long, flat creatures with segmented bodies. They can grow up to 12 inches long in dogs. Mature segments can detach from the tapeworm’s body. These pieces get pooped out and are often the first sign your dog has a tapeworm. You may see these segments directly in the stool, around your dog’s anus, or in their bedding.
While humans don’t get tapeworms directly from dogs, it is possible for a human to accidentally ingest an infected flea, which can result in tapeworm infestation.
Hookworms
Hookworms get their name from their small, hook-shaped mouths. They are tiny, measuring only a quarter of an inch long, and can be almost impossible to notice. The main species affecting dogs include Ancylostoma caninum, Ancylostoma braziliense, and Uncinaria stenocephala. Hookworms consume a lot of blood in the intestine, which can cause anemia, especially in puppies.
Dogs contract hookworms through ingestion of larvae in an environment contaminated with feces, direct penetration through the dog’s skin, or ingestion of animal hosts with infective larvae. Puppies can get hookworms directly from their mom’s milk, as well. These worms will take up residence in the dog’s small intestine, where they will attach and feed directly on the dog’s blood.
The most common signs of hookworm infestation include pale mucous membranes, anemia, failure to gain weight, poor hair coat, dehydration, and dark, tarry stools. When the worms penetrate through the skin, they can cause an area of redness and itchiness, usually on the feet.
Like roundworms, the eggs are microscopic. You are unlikely to notice hookworms in your dog’s stool. Hookworm larvae in contaminated soil can penetrate human skin.
Whipworms
Whipworms are another small worm, measuring a quarter of an inch in length. The main species affecting dogs is Trichuris vulpis. Dogs contract whipworm by ingesting infective eggs or other materials contaminated with feces. Whipworm eggs are extremely hardy, illustrated by their ability to survive on surfaces for up to five years! Once the whipworms are in your dog’s body, they’ll mostly take up residence in the small intestine.
Chronic diarrhea is the most common sign of a whipworm infection, along with lethargy and abdominal pain. The diarrhea may have a lot of mucus or fresh blood.
Like both roundworms and hookworms, eggs are microscopic, and you’re unlikely to notice adult whipworms in your dog’s stool.
Worm Appearance at a Glance
|
Worm |
What It Looks Like |
Usually Visible? |
|
Roundworms |
Spaghetti-like worms |
Sometimes |
|
Tapeworms |
Flat, rice-like segments |
Often |
|
Hookworms |
Tiny, thin worms |
Rarely |
|
Whipworms |
Small with a narrow head and thicker tail |
Rarely |
Deworming Schedule
Deworming plays a critical role in your puppy's care. Young dogs are especially vulnerable to worm infections, so a consistent schedule matters.
Puppies can acquire certain worms through the placenta before birth or through their mother’s milk after birth, which is why deworming starts early.
|
Age |
Deworming Frequency |
|
2 weeks to 2 months |
First treatment |
|
2–6 months |
Every 2–4 weeks |
|
6 months and older |
Every 3–6 months |
Puppies face a higher risk of reinfection. Their immune systems are still developing, and they explore the world with their mouths. Vets often give these treatments alongside your puppy's vaccines.
As your puppy gets older, follow your veterinarian’s recommended schedule for year-round broad-spectrum parasite control. The appropriate product and frequency depend on which parasites it targets and your dog’s risk factors.
Even if your dog receives year-round broad-spectrum parasite control, puppies should have fecal testing at least four times during their first year. These tests help detect infections that may otherwise go unnoticed.
Deworming Side Effects
Deworming medications are safe and effective. Mild side effects can appear as your puppy's body expels the parasites. Here's what to expect, and when a symptom needs your vet's attention.
Diarrhea
Mild diarrhea is a common and normal response to deworming. The medication irritates your puppy's digestive tract as it works, and dead or dying worms can trigger temporary digestive upset. Some puppies also vomit or lose their appetite for a day.
When it's normal: Loose stool lasts a day or two, your puppy keeps drinking water, and their energy stays close to normal.
When to call the vet: Diarrhea lasts more than 2 to 3 days, your puppy vomits repeatedly, or you notice signs of dehydration like dry gums or sunken eyes. Rarely, a heavy worm burden can block the intestines. Treat straining to defecate, a swollen belly, or a refusal to eat as an emergency.
Mucus or Blood in Stool
Mucus or blood in your puppy’s stool may result from intestinal irritation caused by parasites, but it can also indicate another health problem.
When it's normal: A small amount of mucus appears once, your puppy otherwise seems well, and the stool returns to normal.
When to call the vet: Contact your vet if you see blood, persistent mucus, or dark, tarry stool. Seek urgent care if there is a large amount of blood or your puppy also has repeated vomiting, weakness, pale gums, or severe lethargy.
Lethargy
for a short time after deworming. Keep fresh water available and let them rest. If lethargy lasts more than a couple of days or comes with other symptoms, check in with your vet.
Tips for Supporting Your Puppy During Deworming
Know When to Feed After Deworming
If your puppy just took their dose, wait about 1 to 2 hours before offering a full meal. This gives the medication time to absorb properly. Follow your vet's specific instructions if they differ, as some products require a different approach.
Ensure Proper Hydration
Deworming can lead to mild dehydration due to diarrhea. Keep plenty of fresh water available.
Use Supplements
Supplements can support healthy digestion and overall well-being during recovery. Ask your veterinarian to approve any supplement before you give it to your puppy.
Final Thoughts on Deworming Your Puppy
Deworming helps protect your puppy from harmful intestinal worms. Most dewormers start working within 12 to 24 hours, although the timing varies by medication, and your puppy may pass worms for several days. Follow the recommended schedule and watch for side effects.
Keep fresh water available and give your puppy time to rest. Contact your vet if diarrhea, vomiting, or lethargy becomes severe or persists, or if you notice blood in your puppy’s stool.
Let’s Answer Your Questions
How long will my puppy poop worms after deworming?
Your puppy may pass worms in their stool for up to 7 to 10 days after deworming. Most dewormers start working within 12 to 24 hours. Your puppy may pass both live and dead worms during this time. Some puppies also need repeat treatments to clear the infestation completely.
How quickly does dewormer start working?
Most dewormers start working within 12 to 24 hours after your puppy receives the treatment. The medication kills worms in the digestive tract, and your puppy’s body then expels them naturally.
Is it normal to see worms in my puppy’s poop after deworming?
Yes, seeing worms in your puppy’s poop after deworming can be normal. The medication kills worms in the digestive tract, and your puppy’s body expels them through the stool. You may see live or dead worms for several days.
What do worms look like in puppy poop?
Worms can look different depending on the type. Roundworms often look like moving spaghetti, while tapeworm segments can look like rice. Hookworms and whipworms are usually difficult to see because they are very small.
How often should puppies get dewormed?
Puppies should generally receive their first deworming at 2 to 3 weeks old and then receive treatments every 2 to 4 weeks until 16 weeks old. After 4 months, vets recommend deworming every 3 to 6 months. Follow your veterinarian’s recommended schedule for your puppy.
What are the side effects of deworming a puppy?
Mild diarrhea, temporary appetite loss, vomiting, mucus or a small amount of blood in the stool, and tiredness can occur after deworming. Monitor your puppy closely during recovery. Contact your vet if diarrhea lasts more than 2 to 3 days, vomiting continues, blood persists, or your puppy shows signs of dehydration.
Can puppies get worms from their mother?
Yes, puppies can get certain worms from their mother before birth or through her milk. Roundworms and hookworms can pass from mother to puppy through milk, while roundworms can also infect puppies in the womb.
Should I give my puppy food after deworming?
If your puppy has just received a deworming dose, wait about 1 to 2 hours before offering a full meal. This gives the medication time to absorb properly. Always follow your veterinarian’s specific feeding instructions if they differ, because some deworming products require a distinct approach.