Puppy Loose Stool After Vaccination? Here’s What You Should Do!

Everyone wants their furry friends to be happy and healthy, and vaccinations are a prime method of ensuring their safety by preventing diseases.

Vaccines can prevent hepatitis, distemper, heartworms, and other nasty conditions. However in some cases, these safety precautions can have unfortunate side effects as well- especially in response to an allergy!

Let’s say you bring your puppy home after vaccinations and they act weak and sick. This is to be expected, but it’s still hard to watch. It’s when conditions start to worsen that you might need to act.

If you’re here on this page right now, the question to ask is: Does your puppy have loose stool after vaccinations?

One of the most common long-lasting symptoms of vaccination is loose stool, or diarrhea. Luckily, this is rarely life-threatening and in most cases will work itself out without any extra medical treatment.

It’s definitely a good idea to withhold food from your puppy while it is experiencing loose stools, as this will help its stomach recover more quickly. Once bowel movements start to become normal again, you can then slowly transition with liquids and small meals.

Some supplements and medications may also be helpful in making your dog feel better. These can include natural remedies like slippery elm and marshmallow root, which contain properties that will help to soothe the digestive tract.

Why Do Puppies Get Vaccines?

Retriver puppy getting vaccinated
veterinary vaccinating a golden retriever puppy

To understand why some puppies get such severe reactions, let’s examine what vaccines actually are.

A vaccine is a sample of dead or altered microorganisms that a veterinarian administers to a puppy’s body.

It provokes a response from the immune system, which learns to fight that microorganism so that it can do so again if it encounters that organism in the future.

Since vaccines are samples of harmful pathogens, it isn’t too surprising that they can be unpleasant.

Not all dogs receive the same vaccines, but some are more common than others. Depending on your geography, some infections are at a higher risk than others.

Several are so common that vets consider them to be ‘core’ vaccines, meaning they are recommended for all dogs by the American Animal Hospital Association. Vaccines that are included are the distemper virus, parvovirus, adenovirus-2, and rabies virus.

What Are Some Vaccine Side Effects In Puppies?

For most puppies, the side effects are little more than fatigue and soreness. In these cases, allow your dog to rest, and they will be fine. Some dogs develop fevers or mild vomiting.

However, other dogs experience loose stool. While this isn’t a definite sign of lasting damage or danger, it should be taken seriously, especially if it is persistent.

Most likely, side effects will begin in the two days following vaccination. They’re generally short-lived, not lasting longer than a few days after that.

Severe allergic reactions typically occur within minutes or hours after vaccination, and those are the ones that merit the most caution.

If it happens before you leave the vet’s office, they’ll be able to advise you. However, things get trickier if symptoms don’t begin until your puppy arrives home.

How To Stop Post-Vaccination Diarrhea

Basenji puppy sick

If your dog does get post-vaccination diarrhea, you can take some steps at home to alleviate the issue.

Some dogs will stop eating when they have stomach problems. This is for the best. Don’t try to get your dog to eat. If your dog does still try to eat, stop them!

Withhold food for 12-24 hours, allowing your dog’s stomach to rest and heal. If that worries you, start at just 6-12 hours without food or water, as that is often enough time.

Once your puppy’s diarrhea stops or significantly slows down, start by offering water.

Then, switch to a bland diet until the stool is normal. Try boiled boneless chicken and plain white rice. Celery and chopped carrots are also good choices. Serve food after it cools, and start with small portions.

The information above pertains to stopping your puppy’s loose stool, but what about helping their bodies heal afterward? There are loads of supplements and natural remedies that can help your puppy get back to feeling like its happy, energetic self.

How To Help Your Puppy Feel Better

Puppy covered in blanket relaxing with human

Different dogs respond to different remedies, but there are a few that are tried and true. Slippery Elm is a safe and effective herb that helps soothe mucous membranes.

L-Glutamine is an amino acid that aids in repairing intestinal cells. Marshmallow root is another herb that soothes a dog’s gastrointestinal tract.

Digestive enzymes provide the live enzyme a dog would get from a natural raw food source. You can easily find these supplements and many more at health food or pet stores.

Prebiotics and probiotics can also help resume regular activity in your puppy’s gut, so try these as well.

Probiotics are helpful even when your dog isn’t sick. Try using them regularly to improve overall gut health. They can be especially helpful if your dog is on antibiotics, just don’t give it to them at the same time.

Prebiotic supplements are fibers that pass to the colon, then ferment into short-chain fatty acids which support your dog’s digestive system by prohibiting antagonistic bacteria growth.

They also provide an energy source to cells, and maintain a proper balance of electrolytes and fluids. Just be sure to use them in conjunction with probiotics!

Unfortunately, dogs often do need to be reimmunized throughout their life.

Vet surgeon giving vaccination

If adequately vaccinated, a dog’s immunity should last more than a year- and sometimes even longer than that. However, immunity does fade over time.

Vaccines have gotten more effective, but the average dog that is low risk will need to receive core vaccines every three years or so.

If your dog has trouble during their initial immunization, consult your veterinarian about the initial steps you can take to ease the process.

Some puppies are also more sensitive to vaccine reactions than others. If that’s the case with your dog, there are steps you can take to help minimize your pet’s discomfort.

Your vet might instruct you to administer an appropriate antihistamine like Benadryl at home before heading to the appointment. It’s also likely that you can spread out vaccinations over a longer duration than just one day.

This way, your young puppy’s body will have more time to adapt and take care of loose stool naturally.

While there are many steps you can take to help your dog alleviate his diarrhea, it is crucial to know when it is time to bring in a professional.

If after a few days, your puppy is still struggling and nothing is working, don’t be afraid to contact your veterinarian and set up a new visit.

Vaccinations exist to help your dog stay healthy and fit for as long as possible, and they can’t do that if they make your furry friend sick and miserable for longer than expected.


If you find that your puppy is experiencing loose stool after vaccinations (whether that be during the daytime or nighttime), rest assured that diarrhea in puppies is a relatively common side effect that usually resolves itself quickly.

While vaccines are vital in preventing otherwise dangerous diseases in dogs, they can also be a bit harsh on a canine’s body at first as the immune system gets used to its effects. Allergic reactions in particular can be severe and should be taken seriously.

If you notice your puppy having diarrhea or other stomach issues after shots, the best course of action is to stop giving it food for the next 12-24 hours. This will allow its digestive system a chance to rest.

Once the loose stools begin to subside, you can start to give small amounts of water to make sure that your pup stays hydrated. Slowly work back to solid food with small meals to avoid further upset.

Some supplements like slippery elm, marshmallow root, and pre/probiotics can also be helpful in soothing and rebuilding the gut after a traumatic event. Don’t hesitate to call your vet to discuss any other concerns or questions that you might have!

Leave a Comment