Causes of Yellow Diarrhea in a Dog

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Diarrhoea is an intestinal disorder common among dogs. Often, if your pet is overcome with irregular and overly fluid bowel movements, it should cause no great alarm. Other times, depending on the intensity and appearance of the diarrhoea, you should contact your veterinarian as soon as possible.

Abnormal bowel movements can appear in a variety of colours, depending on the cause. Yellow diarrhoea in particular can be caused by stress, a reaction to a medication, or the ingestion of inappropriate materials (such as trash). Another common cause is a reaction to a specific food, organism, or virus.

Reactions to Food

Problems with your pet’s diet can lead to bouts of yellow diarrhoea. Intolerance of or an allergic reaction to a certain food, an abrupt change in diet, and indigestion are all possible causes. Additionally, if you feed your dog table scraps or if he eats something outside, such as leaves or grass, he may experience diarrhoea as well. Paying attention to your dog’s dietary habits will prepare you for any possible outbreaks. If you do notice that your dog’s stool is yellow and fluid, inspecting the stool may help you figure out the cause of his diarrhoea.

Giardia Canis

Giardia canis is a parasitic infection that causes yellow diarrhoea. Giardia are protozoa, unicellular microorganisms that move about via whiplike tails called flagella. Giardia are ingested while in their cyst form. These cysts then implant themselves in the dog’s small intestine, where they open and the protozoa’s active form, called a trophozoite, is released. The organisms begin to multiply and pass into the faeces, causing yellow diarrhoea. If left untreated, Giardia infections can lead to disease, and bouts can range from acute to chronic. It’s important to contact your veterinarian in order to diagnose and treat Giardia canis.


Parvovirus is a viral infection that occurs predominantly in puppies and can be fatal if not treated. The viral strain attacks rapidly dividing cells; cells multiply the fastest in the gastrointestinal tracts of growing puppies. The virus passes through a dog’s faeces, causing yellow diarrhoea. The virus then can easily be transmitted to other dogs when they eat the infected stool or simply breathe in the parvovirus in the stool. While parvovirus tends to be the immediate diagnosis for dogs with yellow diarrhoea, it is often misdiagnosed. Dogs infected with the virus usually experience other symptoms along with diarrhoea, such as vomiting and depression. As with Giardia canis, it’s imperative that you contact your veterinarian in order to diagnose and treat the virus.