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Common Causes of Diarrhea in Dogs

Pet diarrhea is not a topic many pet owners want to discuss. But as any trusted emergency vet near Fort Collins will tell you, there are numerous factors that can affect your dog’s digestive tract, resulting in diarrhea, and it’s important to know about them. Diarrhea can be a dangerous symptom because it can dehydrate your dog quickly. It can also be characteristic of more serious health problems.

In most cases, dogs may have a loose bowel movement from time to time because of something they ate, a mild reaction to anxiety or other minor factors. However, if your dog is struggling with diarrhea consistently for 12 hours or more, you should take them to an emergency vet immediately.

Common Causes of Diarrhea in Dogs:
Dogs, like humans, have a very delicate and balanced digestive system. When that balance is disrupted, digestive distress symptoms, such as diarrhea, can occur. Many causes of diarrhea are not severe, but some can be more serious. Here are the most common causes of diarrhea in dogs:

  • Dietary indiscretion: Dogs are not good at regulating their diet. Eating too much at meals, eating garbage, and eating spoiled food or grass can lead to diarrhea. Usually, unless your dog ate a great deal of something he shouldn’t have, the problem may not require hospitalization.
  • Change in food: Sometimes, when a dog’s food is switched without gradually mixing more of the new in with the old to transition them, indigestion and diarrhea can occur.
  • Food intolerance: This can be more serious because it means there’s an ingredient in the food the dog is eating that is causing digestive problems. A qualified veterinarian will be able to diagnose food intolerance in this case.
  • Allergies: Some allergic reactions to food or medication result in diarrhea.
  • Parasites: Several common parasites, such as roundworms and giardia, can cause diarrhea in puppies or adult dogs.
  • Poisonous substances or plants: This cause can be extremely serious. Often other symptoms occur with diarrhea. If you have any suspicion at all that your dog’s runny stools are the result of a poisonous substance in his system, rush him to a vet immediately.
  • Swallowing an indigestible foreign body: This can also be very dangerous. Swallowing a toy, socks, or other inedible object can block the digestive tract and cause diarrhea. If you suspect your dog has a foreign body in its digestive system, see a vet immediately.
  • Bacterial and viral infections: Consistent and/or worsening diarrhea can be a symptom of bacterial infections such as salmonella, or viral infections like parvovirus, distemper, and coronavirus, all of which require medical treatment.
  • Serious illnesses: Kidney and liver disease, colitis, inflammatory bowel syndrome, and some forms of cancer.
  • Antibiotics and other medications: Antibiotics especially have properties that cause diarrhea readily in dogs.
  • Anxiety, stress, or emotional upset: Sometimes, when dogs find themselves in a stressful situation, it manifests itself in diarrhea.

Watching for Abnormal Stools
As a dog owner, you’re no stranger to picking up after your dog. You’ve likely gotten used to the normal consistency of your dog’s stools when he’s feeling well. If you notice any change in your dog’s bathroom habits, consistency, color, shape, size, and content that can’t be easily explained, contact your local emergency vet.

Obviously, diarrhea is known mostly for its consistency. Loose stools are likely a sign of one of the causes mentioned above. But in addition to consistency, you should take note of the color, shape, and if it seems to be too little or too much for what your dog has been eating.

Contact your vet if you have any reason to believe your pet has a bad case of diarrhea that won’t subside after a couple of hours, don’t hesitate to contact your local emergency vet. You can connect with Royal Vista Vets 24/7, just minutes off of I-25 near Fort Collins.


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Royal Vista Veterinary Specialists


4630 Royal Vista Circle, Ste 11 Windsor, CO 80528

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Emergency department: Friday-Sunday: 24 Hours Monday: 12:01 AM - 9:00 PM Tuesday-Friday: 9:00 AM - 9:00 PM Surgery Department: Monday-Friday: 8:00 AM - 5:00 PM (by appointment only) Internal Medicine Department: Tuesday-Friday: 9:00 AM - 5:00 PM (by appointment only)