My Puppy Died After Deworming – How did this even happen?

Just like humans, puppies need to be dewormed regularly. After all, worms are dangerous and can make your dog chronically ill. What’s more? They are more common in puppies than in adult dogs and can even cause growth stunting.

In short, yes puppies can die after deworming if they are not dewormed frequently enough. That’s why puppies should be dewormed more regularly than adult dogs. While the latter can safely last 3 months between their deworming sessions, the former need one every 2 to 3 weeks.

If a puppy is not dewormed for a substantial period of time and then is dewormed, it can cause intestinal blockages that lead to a sudden death.

This can be particularly worrying if one of your friends or family members has ever told you that their puppy has died after deworming. So, can this happen to your puppy too? Well, that’s what we’re going to talk about today. 

Can Deworming Cause Death in Puppies?

Deworming can cause death in puppies. This is particularly common among puppies with a heavy worm load. Such puppies usually live in areas with a lot of worms and are not regularly dewormed. When these puppies are eventually dewormed, the lump of dead worms that accumulates in their intestines can cause damage.

They can particularly make it hard for your dog to pass stool and all the accumulated worms. This can cause symptoms like squealing, restlessness, pooping blood, and vomiting of worms. In some rare cases, your puppy can even have seizures and enter a coma. Generally, this process is excruciating and can last days before your puppy dies. 

So if you notice any of the abovementioned symptoms in your puppy after you deworm them, take them to the vet immediately. More importantly, try to avoid this whole situation altogether by regularly deworming your puppy. Also, always ensure that your dog’s environment is clean. Pick up their stool as soon as possible, and remember to wash your hands immediately after. 

Can Puppies Overdose on Worm Medicine?

Puppies can overdose on worm medicine if you feed them 10 to 20 times the recommended dose. Keep in mind that some puppies are more sensitive to worm medicine than others. For instance, Australian shepherds, German shepherds, and Collies have been known to have a genetic sensitivity to the dewormer Ivermectin.

Whatever the case, though, giving your puppy more worm medicine than it can handle can allow the drug to get to its brain and cause damage. 

So you need to be careful when feeding them to your dog. Always ensure that you get the dose just right and don’t deworm your puppy more frequently than recommended. Also, pay attention to how your dog reacts to specific worm medicines. If you notice that they are sensitive to it, consider switching to another with the help of your vet. 

Another thing you need to remember when it comes to deworming is that you need to be patient. So if you feed your puppy some dewormer and don’t see them pass the worms the same day, don’t just feed them additional worm medicine – this can lead to an overdose. Ultimately, it’s best to consult your vet on this matter first so that they can know for sure what to do next. 

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

Since dewormers are usually extensively tested for safety, the chances of your puppy dying from taking them is low. This happens in rare cases and is usually caused by overdosing, heavy worm loads, and consistently using dewormers that your dog is sensitive to.

So as long as you regularly and carefully deworm your puppy, they’ll be fine. Just to be safe, you can even have your puppy’s first deworming session at the vet’s office. 

This is particularly a good idea when you have a newborn puppy. These puppies are vulnerable and need to be dewormed at around 2 weeks old. This is supposed to ensure that any worms that they got from their moms are killed before they pass any eggs in their stool. After this first session, you can deworm them every 2 weeks until they’re 8 weeks old; then, you can deworm them less frequently. 

There’s one thing you need to keep in mind, though – you may still have to take your adult dogs to the vet’s office for deworming. Most over-the-counter dewormers deal with roundworms and other common worms. For some worms and parasites, your dog can only get diagnosis and treatment at the vet’s office. 

How Do I Know if The Deworming Killed My Puppy?

If your puppy was healthy before you dewormed them but then became sick soon after and died, there’s a high chance that the deworming is what killed them. But even then, only your vet can tell you this for sure. Sometimes symptoms like restlessness and blood in poop can be caused by ingestion of a foreign body. This could especially be the case if you have been regularly deworming your puppy without any health incidents. 

However, if your puppy is sensitive to a certain dewormer and you insist on using it, and they get sicker than usual and die, it’s obviously the deworming that has killed them. Ultimately, it’s important to understand which dewormers are suitable for your puppy. Research the worm medicines available to you and include your vet in the decision when possible. This will allow you to make an informed decision and prevent any accidents.

Don’t let this process discourage you from deworming your puppy, though. It’s generally a safe and straightforward process. Also, avoiding deworming can lead to worm infestations that can cause lethargy, vomiting, weight loss, and diarrhea. If left untreated, worm infestations can even make your puppy faint or kill them. 

Dewormer Overdose Symptoms

Some common dewormer overdose symptoms include tremors, seizures, comas, dilated pupils, breathing problems, and even death. Ivermectin overdoses are particularly deadly and need aggressive treatment. As such, you should take your puppy to the vet immediately if they exhibit more than one of the abovementioned symptoms. There’s one thing you need to keep in mind, though – dewormers do cause some side effects that you don’t need to worry about. 

These include vomiting, diarrhea, drooling, and lack of appetite. These are usually caused by worms releasing toxins as they die, making your puppy’s stomach upset. So when you notice these symptoms, sit patiently with your dog and monitor them so that things don’t escalate. Most times, these symptoms subside within 24 hours. 

So as long as your puppy has access to water and food, it should be fine. Just keep a lookout for any overdose-related symptoms, even if you’re sure you gave your puppy the right dose. They could be sensitive to the worm medicine or have accidentally ingested horse dewormer. In some cases, your dog could even have ingested the feces of a horse that has recently been dewormed. 

My Puppy Died After Deworming and Vaccine

If your puppy dies after you deworm and vaccinate it, either or both of the procedures could be the root cause. Alternatively, the puppy could have contracted a common disease such as Parvovirus. This is especially common among puppies that are exposed to other dogs. So if your puppy dies suddenly, always remember to test your other puppies for Parvovirus and other common diseases. 

Once you rule out disease, you need to look into whether you overdosed your puppy with dewormer accidentally, exposed them to fecal matter from dewormed animals, or gave them dewormer they were sensitive to. But if none of these are the case, the only explanation for your puppy’s death would be a vaccine allergy. While rare, vaccine allergies can be lethal. And they usually start off with one major symptom – loss of appetite.

Other symptoms of vaccine allergies include hives, vomiting, diarrhea, lethargy, swelling/redness around the vaccination site, anaphylactic shock, and collapsing. While the last two symptoms are severe and need medical intervention, the first five are minor and are to be expected. Fortunately, during the vaccination, your vet usually tells you what symptoms to expect, what to do when things escalate, and when to bring your puppy back to them. For instance, they may advise you to administer Benadryl when you notice certain symptoms – 1mg per pound of puppy every 8 hours is usually the ideal. 

What Should I Do if My Puppy Dies After Deworming?

The death of a puppy is always heartbreaking, especially when they die after a routine procedure such as deworming. But once this happens, there’s no point in blaming yourself. The best thing you can do is give yourself time to grieve your pup and try to prevent this from happening again. So if you have other puppies or are planning to get some, work on putting measures in place to ensure that deworming always happens safely.

First of all, you need to set apart entire days for your puppies’ deworming. This ensures that you have time to calm your puppies beforehand, monitor them after deworming, and offer any food or water they need. It will also give you enough time to research the most suitable dewormer for your dog and the proper dosage. Ultimately, this level of attention and presence leads to fewer dosing and sensitivity problems. 

There’s one thing you need to remember, though – it takes a few days for your puppy’s body to completely get rid of all the worms in its intestines. So for a few days after you deworm your puppy, you will notice some dead worms in their poop. If you notice that these worms are alive, your puppy will need a second round of deworming. To avoid overdosing, it’s important to consult your vet before you do this, though. 

My Puppy Died at The Vet While Being Dewormed – What Should I Do?

While it’s rare, your puppy can die at the vet’s while being dewormed. This is a painful experience, and few dog owners ever see it coming. However, it’s not a reason to get mad at your vet or blame them. Instead, it’s an opportunity to examine what went wrong and come up with strategies to avoid this situation in the future. 

First of all, you can talk to your vet to get an understanding of the circumstances around your puppy’s death. If you’re not satisfied with the information you get, you can even request an autopsy. This can give you clarity on the reason why your puppy died during deworming. Don’t just assume that the deworming procedure is what killed your puppy. 

It could be that they were sick beforehand, and the stress of the deworming process was just the last straw. Alternatively, it could be that your puppy was hypersensitive to the dewormer administered, and your vet didn’t know. Either way, having this information will help you and your vet to safely deworm other puppies you encounter in the future. However, it’s ultimately up to you to decide whether you want to use the same vet again – you get to choose what changes you want to make after your dog’s death. 


For the most part, deworming is safe, even for 2-week-old puppies – worm medicines have been rigorously tested to ensure this. However, things can occasionally go south, resulting in serious symptoms like seizures and comas – your puppy can even die after deworming. So when this happens, don’t blame yourself or your vet – accidents happen. Instead, take time to grieve, try to learn from the experience, and implement your lessons when deworming other puppies in the future – this way, you can get some meaning from the loss. 


  • Brad

    Hi I'm Brad, the founder of Having been a vet of 6 years I work alongside our team to provide valuable insight into your dog's health. I have a frenchie myself named Senzu who is my pride and joy!