Puppy Shots & Diarrhea

By Jane Meggitt

Puppies need vaccinations to stay healthy and avoid serious disease, but some shots may cause side effects, including diarrhea. While diarrhea in older dogs might resolve itself within a day, diarrhea in puppies with their immature immune systems can lead rapidly to dehydration. Call the vet if a puppy has diarrhea after getting its shots.

Puppy Shots

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Puppies should not be vaccinated until they are weaned. Before the age of approximately 8 weeks, puppies receive antibodies from their mothers' milk, and vaccinating before this time can result in lesser vaccine efficacy. Postpone shots until after 8 weeks if the puppy is sick or malnourished.

Vaccination Schedule

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The recommended protocol for core puppy shots includes vaccinations against canine distemper, parvovirus and hepatitis. Rabies vaccinations are also important, but are generally given separately from the core vaccines. The core vaccines are injected in a combination shot, with two booster shots given at three-week intervals. Non-core vaccinations include those for bordatella, coronavirus and parainfluenza. Consult a veterinarian as to their recommendation for non-core shots for a particular puppy or for certain regions.


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An adverse reaction to shots is called vaccinosis. One adverse reaction is diarrhea. Diarrhea in puppies is a serious matter. It can cause dehydration if severe. Most puppies will suffer mild bouts of diarrhea, but call the vet if the puppy has a large amount of watery stool over more than a few hours.

Other Causes

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Other causes of diarrhea in puppies includes worm infestation. Roundworms are very prevalent in puppies, and may be passed from their mothers. Pot-bellies, poor coats, vomiting and a general unhealthy appearance are signs of intestinal parasites. If untreated, worms can be fatal. They cause intestinal obstruction or pneumonia if they travel to the lungs. Veterinarians will worm puppies as part of basic checkups.

Risks of Not Vaccinating

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While diarrhea is a common side effect of puppy shots, the risks of not vaccinating are far worse than this minor inconvenience. Puppies contracting parvovirus and distemper suffer high fatality rates. Diarrhea is a symptom of both diseases.

The highly contagious parvovirus attacks cells in the intestinal lining, leaving puppies unable to absorb liquids or the nutrients in food. Terrible, bloody diarrhea and severe dehydration ensue. Distemper, also very contagious, begins with fever, coughs and nasal discharge. The intestinal tract is also affected, with vomiting and diarrhea. It progresses to the brain, causing seizures. This incurable disease kills most of its victims, and survivors often suffer from neurological disorders.

Remedies and Prevention

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For any dog, dietary changes should be made gradually. For puppies experiencing mild diarrhea, however, adding cooked rice to their canned or dry puppy food can help solidify stools. Chicken broth can give both nourishment and liquids to prevent dehydration. Make sure there is always water available.

If the puppy suffers from vaccinosis, ask the vet if giving a homeopathic remedy may help. The homeopathic remedy thuja (30c), if given two hours before shots are scheduled, may help prevent another vaccinosis episode. You can squirt the liquid directly into the puppy's mouth. Thuja is obtainable from a holistic vet or health food store.