When to Worry: Signs of Concern for Your Dog’s Diarrhea

If your dog has diarrhea, it can be worrying. While it’s normal for dogs to have occasional loose stool or diarrhea, it can also be a sign of an underlying health issue. It can be difficult to know when to worry, so here are some signs that indicate you should take your dog to the vet.

Sudden onset of diarrhea

If your dog’s diarrhea comes on suddenly, this can be a sign of an urgent health issue. If your dog was perfectly fine one moment and then started to have diarrhea, it could be an indication of poisoning or gastrointestinal discomfort.

Blood in the stool

If there is blood in your dog’s stool, it can be an indication of something serious. Blood in the stool can indicate a gastrointestinal infection, inflammation, or even cancer. It’s important to take your dog to the vet as soon as possible if this is seen.

Continued diarrhea

While occasional diarrhea may not be cause for alarm, continued diarrhea should be a concern. If your dog has diarrhea for more than 24 hours, it could be an indication of an underlying health condition.

Loss of appetite

Diarrhea can affect a dog’s appetite. If your dog has diarrhea and is not interested in food, it could be an indication of a more serious health issue. Loss of appetite can be a sign of everything from an upset stomach to cancer.


Diarrhea can lead to dehydration. If your dog is drinking less water than usual or has symptoms like dry gums or lethargy, it’s a sign that they are dehydrated. Dehydration can be caused by a range of health problems and requires urgent attention from a vet.

Frequent vomiting

Frequent vomiting can be a sign of a serious health issue. If your dog is vomiting alongside having diarrhea, it’s a sign that they are ill and require veterinary attention.


If your dog has a fever alongside their diarrhea, it could be a sign of an infection. A fever can indicate a bacterial, viral or parasitic infection, which will require veterinary attention.

Changes in behavior

Diarrhea can be stressful for a dog. If there are changes in behavior, such as uncharacteristic lethargy, anxiety, or irritability, it’s a sign that your dog is unwell and should be taken to the vet.

Unusual color or odor of stool

While dogs have different stool appearances, unusual color or odor could be a sign of a health issue. If the stool is black, contains mucus, or has a significantly different smell, it’s an indication that your dog is unwell.

Ongoing or recent medication

If your dog is currently taking medication or has recently had their medication changed, it could be a possible cause of diarrhea. Some medications may cause diarrhea as a side effect. Consult with your veterinarian if you suspect this.

Traveling or diet changes

If you’ve traveled with your dog or changed their diet recently, it can cause diarrhea. Keep track of any dietary or environmental changes to identify the source of the diarrhea.

Parasite infestation signs

Parasites can cause diarrhea in dogs. Look out for symptoms like worms in stool, bloating, and lethargy. Take your dog to a veterinarian as soon as possible if symptoms are found.

Post-Surgery Diarrhea

If your dog has undergone surgery recently and is experiencing diarrhea as a side effect, consult with a vet, as it can be an indication of a severe infection.

Rectal Bleeding

If you notice rectal bleeding in your dog, including irritation and redness, it can signify other health issues like anal gland problems or ulcers, and stomach tumors or other internal trauma. It is important to take your pet to a veterinarian urgently.

Diarrhea in Puppies

Puppies have a weak immune system and have a higher risk of contracting parasites and infections that can cause diarrhea. This, along with dehydration, can cause severe damage or even death to a puppy. It is, therefore, important to monitor the puppy’s behavior and stool regularly and see a vet as soon as possible if symptoms occur.


Diarrhea in dogs can be caused by some reasons, ranging from mild to severe. When a dog has diarrhea, watch the signs of concern like sudden onset, continuous diarrhea, loss of appetite, dehydration, frequent vomiting, fever, changes in behavior, an unusual color or odor of stool, medication, parasite infestation, post-surgery diarrhea, rectal bleeding, and diarrhea in puppies. Consult a veterinarian as soon as possible when signs occur.


  • Q: When should I worry about my dog’s diarrhea?
  • A: You should worry about your dog’s diarrhea if it lasts more than 24 hours, has blood in it, and there are accompanying symptoms of uncharacteristic lethargy, anxiety, or irritability.
  • Q: Can dog diarrhea go away on its own?
  • A: Occasional diarrhea can go away on its own without treatment, but ongoing or persistent diarrhea requires veterinary attention.
  • Q: Is it safe to stop feeding my dog when he has diarrhea?
  • A: You should still continue to feed your dog when they have diarrhea but change the diet to prevent worsening the condition. Instead of giving them large meals, feed small meals frequently, bland foods such as chicken and rice, or specific diets prescribed by your vet.
  • Q: Can stress cause diarrhea in dogs?
  • A: Yes, stress and anxiety can cause diarrhea in dogs, especially if they are rehomed or have experienced a traumatic event.
  • Q: Is diarrhea contagious to other dogs?
  • A: Yes, diarrhea can be contagious to other dogs. It’s essential to keep dogs with diarrhea away from other dogs and puppies until they are treated and are symptom-free.


Doyle, M. T. (2017). Diarrhea in Dogs Diagnosis and Treatment. Vet Clin N. Am.-Small Anim. Pract., 47 (2), 375–389. https://doi.org/10.1016/j.cvsm.2016.10.001

Gomez-Gallego, C., Junnila, J., & Serrano, M. A. (2019). A dog’s diarrhea dilemma-amiibo point-of-care test for a rapid identification of infection in canine diarrhea samples. Biosensors and Bioelectronics, https://doi.org/10.1016/j.bios.2018.12.048

Paone, A., Stewart, K., & Lobetti, R. (2021). Infectious agents causing diarrhea in dogs in a shelter in South Africa. Journal of the South African Veterinary Association, 92 (1), 1-7. https://doi.org/10.4102/jsava.v92i1.2001

Leave a Reply

Your email address will not be published. Required fields are marked *