Puppy Died After Deworming (Did Worming Medication Kill My Pup?)

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Puppies are susceptible to a lot of infections and diseases like adult dogs are, including worms. But if your puppy died after deworming, you’re sadly left wondering; did worming medication kill my pup?

We aim to answer this question in great detail within this article.

Since they are very young, immunity isn’t built up yet in a puppy’s body, which is one of the primary reasons they need a lot of care and attention from their owners, so the puppy stays healthy.

One of the earliest treatments that most puppy owners administer is the deworming treatment.

This treatment is given in order to help the puppies eliminate worms and possible parasites inside their bodies.

If you don’t give puppies deworming medications, they could fall severely sick and even die if they contract intestinal worms (or have them already).


If your puppy dies after administering worming medication, then a deworming medicine overdose is likely the most significant cause of puppy death. In rare cases, a bad reaction to deworming treatments leading to serious health problems, may also make the puppy die. Hence, it is always a good idea to consult a veterinarian and treat your puppy according to the vet’s expert opinion.

This article will discuss puppy deworming, whether you need to do it, how safe it is, and some of the side effects.

Can Deworming Kill Puppies?

Unfortunately, the answer is yes. Deworming puppies can unfortunately lead to them dying in rare cases.

There have been a few reported cases of puppy deaths due to deworming.

However, you should note that these deaths are generally due to an overdose of medications, or in rare, severe cases where the new puppy has had a reaction and not simply because of one round of deworming medication.

On the other hand, if puppies are left untreated for a while and not used to getting dewormed regularly when you give them a powerful deworming medication, it can cause an accumulation of excess worms, which will hamper their intestinal functions, potentially causing illness and even death.

Therefore, you must consult a professional veterinarian who knows how to correctly diagnose and prescribe the right amount of medication for your puppy’s treatment.

How Likely Is It That A Puppy Can Die from Deworming?

Most dewormers are tested for safety, so the chances that a typical puppy will die from one or two deworming sessions are very low.

Puppy deaths due to deworming are uncommon, and it usually only happens if there is at least an overdose of 10 to 20 times the recommended dose of dewormer medication.

In rare cases, deworming side effects like diarrhea or vomiting can cause compilations in young puppies, leading to seizures and even coma.

It can last for a few days until the puppy dies, which is highly stressful for loving dog owners.

Although it is possible to deworm your pet at home, to be safe, take it to the vet for a consultation before the deworming session.

Reasons My Puppy Died After Deworming Medication

There are a few reasons why a dewormed puppy may die after being treated.


As with humans, you need to be careful about how much medication you administer to your puppy.

Puppies are already so delicate and fragile, so it’s only fitting to consult a vet and get the proper dosage for the safest puppy care.

Never give your puppy higher doses than recommended

Frequency Of Dosage:

Ensure that you are deworming your puppy only as regularly as the vet recommends.

Don’t go over the dosage frequency at your convenience or because you think it’ll be better for the dog’s health. It’s usually the opposite.

Likewise, ensure your first deworming session is done as early as 2 weeks after the puppy is born. This will accustom the pup’s body to the medication.

In other puppies, they have died after deworming because they had accumulated too many worms in their body.

The medication kills all the worms, causing the intestines to get blocked due to excess dead worms.

Eventually, this leads to the puppy’s untimely and sad death.

Bad Reaction:

It is normal for puppies to react with a bit of lethargy, diarrhea, or appetite loss as these are potential side effects, but if the symptoms persist and become severe, take the pup to the vet.

These symptoms should only last about 24 hours.

Reactions like bloody stool, seizures, and breathing problems are not typical side effects of deworming medicine.

If you notice any of this, take it to the animal hospital as soon as possible.

Also, look for possible reactions from your dog when you give them the medicine.

The next time you have to deworm your dogs, you can consult the vet and consider changing the medication to another one that won’t cause as much discomfort.

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Side Effects of Deworming a Puppy


This can be one of the immediate side effects your puppy experiences when given the deworming tablet.

If your dog vomits, this is a natural reaction and is normal.

Your puppy might also try to wretch and get the pill out of their system (if you’re using medication in tablet form), causing vomiting.

Keep an eye out to ensure the puppy does not throw the pill or try to hide it somewhere.

Also, give it access to drinking water to avoid dehydration.

Lack Of Appetite

Deworming tablets kill the worms and release toxins, which can cause an upset stomach in many dogs.

Your puppy probably won’t want to eat food after taking the pill, but this is also a normal reaction, so there’s no need to worry.

This should last only 24 hours.

Excess Salivation

This is also linked to the vomiting and nausea side effect in your dog.

When the puppy wants to vomit and has an upset stomach, it can start drooling more than normal.

Ensure you always keep enough water accessible for the puppies to compensate for the fluids they are losing.


This is also a normal reaction to dewormer pills and is caused by the inflammation of killing the worm infection inside their bodies.

It can be coupled with blood in the stool, but it should not concern you unless it persists for 3 days or more.


It’s normal for your puppy to feel lethargic.

After all, puppies can feel unwell after vomiting or experiencing diarrhea.

Make sure you give them time to rest and water to drink.

Extreme Side Effects

If any side effects mentioned above last more than 2-3 days, it’s time to visit the vet.

Apart from this, it would help if you also looked out for these things after deworming your puppy:

  • Seizure and tremors
  • Difficulty breathing
  • Bloody stool for more than 3 days
  • Extreme weight loss (a little bit is to be expected since they’ll lack appetite for a day or two)

Puppy Died After Deworming: FAQs

Below were the most common questions we saw online when researching the topic of puppy death relating to deworming medications and the deworming process:

Can Deworming a Dog Hurt Them?

Yes and no.

Deworming medicines help puppies and dogs eliminate parasites that might cause illnesses.

Although they might experience some discomfort during the first 24 hours after treatment, these side effects are typically short-lived.

A puppy dying after being wormed is quite rare.

Can a Puppy Get Sick from Dewormer?

Yes. Puppies often experience nausea, diarrhea, and vomiting after taking a deworming medicine. This is a normal reaction to the medicine and is no cause for concern.

How Do Puppies Act After Deworming?

After you give your puppy the deworming pill, look for side effects like vomiting and diarrhea. You may also notice excessive drooling and lethargy.

You may also find worms or their eggs in your dog’s feces, which means the drug is working.

These side effects are entirely normal and should wear off in the next 24 hours.

Can Puppies Overdose on Worm Medicine?

Yes. It is possible for dogs to overdose on worm medicine if you give them 10 or 20 times the recommended dosage in rapid frequency.

There is a wide margin, but this should never be tested.

The outlook for a dog is good, even after an overdose, with one even recovering completely from being in a coma (1) for 7 weeks.

Other dogs most common type of symptoms from an overdose was sedation and temporary blindness (2) which they eventually recovered from.

How Do I Know if The Deworming Killed My Puppy?

If you had a relatively happy and healthy puppy that passed away soon after deworming, the deworming likely is what killed your puppy.

But it’s impossible to truly know unless you get an autopsy.

Also, signs like diarrhea, vomiting, bloody stool, seizures, etc. extended for more than 2 days indicate that your puppy had a bad reaction to the drug.


We hope the hours of research that went into this article went some way to explaining whether a dewormer was the cause of death in your puppy.

In reality, it’s impossible to know for 100% sure unless you book an autopsy of your pet whether your puppy being dewormed was what caused the health complications.

Ultimately, the reward of proper puppy care outweighs the very small risk involved in getting your pets dewormed.

If you’ve experienced this tragic event, our condolences to you and your family members. We hope that this article gave you some closure, at the very least.


(1) Ivermectin and piperazine toxicoses in dogs and cats. Vet Clin North Am Small Anim Pract. 1990;20:453–68. https://pubmed.ncbi.nlm.nih.gov/2180189

(2) Toxicology of Avermectins and Milbemycins (Macrocylic Lactones) and the Role of P-Glycoprotein in Dogs and Cats: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4152460/