My Puppy Died After Deworming: Why Did This Happen?

Dogs are always curious about their surroundings. They will sniff, lick, chew or try to gobble down anything new they find. While this is how they navigate the world, it makes them susceptible to worms and parasites.

Deworming is a routine activity to eliminate the worms in your pet’s body. If your puppy died after deworming, we are sorry for your loss. It is understandably a heartbreaking experience.

The medicine used for deworming undergoes several levels of testing. Deworming can lead to side effects like vomiting, diarrhea, and excessive drooling.

It is rare, but there are possibilities of the pet passing away after deworming. An incorrect dosage could be one of the reasons.

The article will explore deworming in detail, reasons the activity could be fatal, and mistakes you should avoid when treating worms in your puppy.

Deworming: What is It? Why Does Your Puppy Need It?

Deworming is the process of getting worms out of your dog’s body. After examining the dog and the type of worm inflicting it, the vet will decide on a deworming medicine. The vet may administer the medication orally, give an injection or use a topical dewormer.

But how do these worms find a way inside your dog’s body?

In newborn and young puppies, these worms can be passed from the mother to the offspring. It can happen at birth or while the mother is nursing the puppies on its milk.

In adult dogs, these worms can pass from one infected dog to another. Or insects like mosquitoes could be carriers of these worm eggs.

Some of the common worms that can affect dogs are:

  • Roundworms
  • Hookworms
  • Tapeworms
  • Whipworms
  • Heartworms

Your puppy could get roundworms, for example, if it sniffs or eats an infected dog’s poop. On the other hand, tapeworms can spread if your puppy comes into contact with fleas infected with the worm larvae.

If left untreated, these worms could turn into severe infections and have systemic effects on your dog’s health. For example, a dog with severe roundworm infection can show signs like:

  • Vomiting
  • Weight loss
  • Potbellied appearance
  • Roundworms in poop and vomit

In rare cases, these worms can be fatal for the pet. Thus, deworming is an essential activity pet owners should undertake for their pet’s health.

How Long Will Your Puppy Take to Poop Worms After Deworming?

It can take anywhere from two to six hours for the deworming medication to work. Then, depending on the medication, the worms will either dissolve or be paralyzed. The paralyzed worms will then be removed from the body through poop.

You can see some of the worms in your dog’s poop. For example, tapeworms are white and look like rice grains or seeds. You may also be able to see roundworms. The adult worms tend to be extra long and white or light brown.

The puppy’s poop may contain worms two to three days after deworming. This is not a cause for concern. The puppy can have other side effects, which we will explore below.

What Are the Side-Effects of Deworming a Puppy?

Here are some of the possible side effects of deworming in dogs.

1. Vomiting

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This is a common side effect of deworming medication. As the medication starts working and the worms die, they release toxins. These toxins can react with the acid in the puppy’s tummy and cause it to vomit.

2. Diarrhea

If your puppy has many worms, they will all accumulate in its intestine after deworming. Its body will then try to push out the worms along with the excess liquid.

This is why your puppy may have diarrhea. And as young puppies will not be house trained yet, monitor your pet because you may have a mess to clean up later.

Also Read: My Dog Has Diarrhea And Keeps Licking His Bum! (6 Reasons To Be Worried)

3. Skin Irritation

Skin Irritation
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If the medication is injected or a topical has been used, your puppy may show signs of local skin irritation. The site may become red and itchy. This should not be a concern as the irritation is typically mild and should resolve independently.

4. Loss of Appetite

The worms reacting with the stomach acids can be nauseous for the puppy. The dying worms can take up space in the dog’s intestine. And if the dog is already suffering from vomiting or diarrhea, it will be in no state to eat.

The side effects mentioned above can be expected, but they should last for around 24 hours, and the puppy should show signs of improvement. If this is not the case, the symptoms continue, or the puppy’s condition worsens, please contact the vet immediately.

Can Your Puppy Die After Deworming?

Yes, this is rare, but your dog could die after deworming. Generally, the medications used are thoroughly tested for their safety and efficacy. They can cause side effects, but these effects usually subside in a day.

If your puppy has died after deworming, here are some possible reasons.

Wrong Dosage

Wrong Dosage
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One of the likely reasons for deworming to be fatal could be that you have administered medicine way beyond the recommended dosage.

In the case of young puppies, they have to be dewormed as early as two weeks old. They have not even weaned off their mother’s milk at this point. Their immune systems are not yet fully functional. That is what makes them susceptible to diseases and infections.

The deworming treatment is the same for puppies and adult dogs. But the dosage requirement significantly varies. If you give your puppy the exact dosage as an adult dog, its body will not be able to handle the medicine.

It could lead to severe side effects and the medication being fatal for the puppy. Therefore, you should consult with the vet before administering any medicine.

Wrong Frequency

As mentioned above, the deworming medication takes about six hours to work. In some cases, though, it may take longer. However, when it does work, you don’t always need to see worms in the dog’s poop.

Do not assume the treatment is not working, and administer another dose of deworming medication. A puppy or an adult dog cannot handle the treatment if you administer medication back to back.

On the other hand, not deworming your pet enough times can also be an issue. There have been several cases wherein puppies as young as four to six weeks old have died due to the sheer amount of worms in their intestines.

Young puppies must be dewormed every couple of weeks until they reach a certain age. If you do not stick to the vet’s recommended frequency, the worms can multiply, sucking all the nutrients from the puppy’s body. In severe cases, the puppy can die due to malnutrition.

Puppies that reach a severe stage might often show symptoms like extreme dehydration, weight loss, stunted growth, and loss of appetite. In such cases, do not try home remedies; instead, visit the vet immediately.

Severe Reaction

Severe Reaction
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This is rare, but your puppy could be more sensitive to the deworming medicine.

For example, ivermectin can be used for deworming with a combination of other medicines. But breeds like Collies and Sheepdogs are sensitive to this medication due to their specific genetic mutation. They can tolerate the dosage used for deworming, but high doses can cause severe side effects.

In other dog breeds, mild side effects are common. But if the dog does not improve in 24 to 36 hours, the symptoms could be pointing to a bad reaction. So, it would be best to contact the vet immediately before the situation turns fatal.

Also Read About: How Long After Eating Does a Dog Poop?

How Often Should You Deworm Your Puppy?

How Often Should You Deworm Your Puppy
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Puppies must be dewormed the first time around when they are two to three weeks old. This treatment kills the worms that have passed to them at the time of birth from their mother.

After a few weeks, the puppies have to be dewormed again to get rid of the worms that may have hatched from the larvae.

Till the puppies are three months old, they may have to be dewormed once or twice a month. The vet can decide on the frequency depending on your pet’s health. Till the puppies are six months old, they may have to be dewormed once a month.

After the six-month mark, the dog may require deworming once a month or once in six months, depending on its condition.

It would be best if you discussed the dosage and frequency of deworming with a vet.

What Mistakes to Avoid While Deworming?

Deworming is a routine treatment as worms are a common issue with canines. If you stick to quality medicine, dosage, and frequency, deworming is safe.

Here are a few mistakes you should avoid while deworming your pet.

Not Confirming the Type of Worm

Not Confirming the Type of Worm
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Several different worms can affect your dog. Usually, broad-spectrum drugs are prescribed as they can effectively kill various worms. But this is not always the case.

For example, roundworms and heartworms have different treatment plans. You can administer the medicine for roundworms, but the medicine for heartworms needs to be administered by the vet only as the medicine can be potent.

Then there can be certain strains of worms for which the vet can prescribe medication only after confirming their presence. So it would be best if you took a poop sample for testing to the vet. The results will help determine the right treatment plan.

Not Weighing the Pet

If you are deworming your dog at home, it is important you weigh the dog beforehand to get the correct dosage. This is because the dog could have gained or lost weight since its last treatment.

Do not assume your dog’s weight because it looks the same appearance-wise. You run the risk of underdosing or, worse, overdosing on the pet.

In case of an underdose, the medicine will not effectively remove the worms from the pet’s body, and it can negatively affect its health. In case of an overdose, the puppy could suffer serious side effects or even pass away.

So make it a habit to weigh the dog before deciding on the dosage.

Not Deworming Regularly

Not Deworming Regularly
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Regarding the treatment frequency, the information provided above is a guideline. Now whether your dog needs to be dewormed monthly, once in two, three months, or six, the vet can only answer the question.

Do not stick to a schedule because your friends do that for their dogs. The lifestyle and health of every dog can be different.

For example, if you have an outgoing and energetic dog, then it will come into contact with more dogs, other animals, and public spaces. Compared to another dog that stays indoors or keeps to the house’s backyard, your dog will be more susceptible to worms. Thus, it may require more frequent deworming than the dog that stays indoors.

Not Considering Expert Advice

Deworming is a relatively easy treatment. In addition, there are several over-the-counter medications available that may be effective on worms. But self-medication is not always the best way to go.

As experienced pet owners, you may think giving the puppy the same medicine with the correct dosage according to its weight is sufficient. And this may work in some cases.

But you do not know if the puppy has some underlying health condition. You may not know the type of worm affecting your pet. There are too many variables involved that you cannot consider from home.

And now that you know the reasons behind the ‘my puppy died after deworming’ situation, it would be best to consult the vet.

How Can You Protect Your Puppy From Worms?

How Can You Protect Your Puppy From Worms
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Worms are a common and known issue in the canine world. Thus, prevention is the best way to protect your dog and yourself, as these worms can spread from animals to humans.

According to PetMD, here are some prevention tips that may help.

  • Fleas can be carriers of tapeworms. Thus invest in flea control medications and collars to keep those pests away. Brush your dog’s coat and bathe it regularly. Clean its paws and fur when it comes home after playing outside. Also, regularly check its fur and use a treatment like medicated shampoos and topicals if you find fleas.
  • Mosquitoes are attracted to still and stagnant water. So make sure you keep your yard and the surroundings clean. If it is a neighborhood problem, then use screens on windows to protect your pet. Certain essential oils can be used as repellants, but it would be safe to use them after a vet consultation.
  • Start obedience training your puppy. Keep them on a leash while you go for walks. This way, if the puppy wanders onto unfamiliar paths or goes sniffing around other dogs’ poop, you can command it not to do so or use the leash to control its movement.
  • Keep up with vet visits. The vet should check your dog for worms a minimum of once a year. In the case of puppies, the vet should do this check two to four times a year.

Also Read: What To Do When Frontline Doesn’t Work: 8 Great Methods


If your puppy died after deworming, we are again sorry for your loss. Deworming is typically safe. It can have side effects like vomiting, diarrhea, and loss of appetite. But these symptoms should resolve in 24 hours.

It is rare, but yes, canines can die after the treatment. The reason for this unfortunate outcome could be medication overdose, incorrect treatment frequency, or a severe reaction.

For deworming to be a safe experience, take the puppy to the vet for a checkup, confirm the type of worm, and stick to the dosage recommendation and frequency.

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