Canine Diarrhea

Canine diarrhea can be acute or chronic, and can be an indication of various possible dog illnesses, from digestive problems to poisoning. This page looks at the likely causes and different characteristics of diarrhea in dogs.

Depending on the diet of an individual dog, most healthy dogs have bowel movements once or twice a day. As well, a normal stool does not contain any mucus, blood, or undigested food.

Diarrhea refers to the passing of loose and unformed stools. Usually, in diarrhea, there is a large volume of stool as well as an increased number of bowel movements.

Diarrhea can be acute or chronic. Acute diarrhea in dogs comes on suddenly and is over in a short period. Chronic diarrhea comes on gradually and persists for a long period of time, e.g. three weeks or longer, or has a tendency to recur.

A majority of canine diarrhea is temporary acute diarrhea with watery, foul-smelling stools. This is the result of foods moving rapidly through the bowel and arriving at the rectum in a liquid state, and is mostly caused by eating inappropriate foods.

Different Characteristics of Canine Diarrhea

Generally speaking, diarrhea can originate in the small bowel or the large bowel, depending on the cause. Diarrhea originating in the small bowel has different color and consistency than that originating in the large bowel. By familiarizing ourselves with the different characteristics of dog diarrhea, we can make a quick judgement as to where the possible problem is from.

Here is a quick reference of the different characteristics of canine diarrhea:

Color	Possible Causes	Possible Location
Yellow, greenish	Food intolerance; dietary indiscretion; upper GI tract inflammation	Small bowel
Black, tarry	Bleeding in upper GI, e.g. stomach ulcers	Stomach or small bowel
Red fresh blood or clots	Bleeding in lower GI	Colon
Light colored	Liver problem, e.g. lack of bile	Liver
Gray colored, rancid smell	Inadequate digestion	Small bowel
Consistency
Watery	Food intolerance; dietary indiscretion; upper GI tract inflammation	Small bowel
Foamy	Bacterial infection	Small bowel
Jelly-like with mucus	Large bowel disorder, e.g. colitis, IBD	Colon
Other Conditions
Weight loss	Digestion or absorption problems	Small bowel, pancreas
Normal appetite, no weight loss	Large bowel disorder	Colon
Vomiting	GI tract infection, e.g. bacterial infection, poisoning	Small bowel

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Causes of Canine Diarrhea

Acute diarrhea can be caused by:

Dietary indiscretion, such as eating garbage, spoiled foods, and indigestible things like plastic, wood, paper and so on.
Food intolerance or food allergies (Depending on the individual dog, some foods that cause intolerance or even allergic reactions include beef, pork, fish, eggs, chicken, corn, wheat, soy, fats, milk, and so on.)
Ingestion of foods or substances that are poisonous to dogs, e.g. antifreeze, grapes.
Sudden, abrupt change of food.
Intestinal parasites (such as worms and Giardia).
Virus infections (e.g. canine parvovirus, distemper).
Side effect of drugs and medications (e.g. NSAIDs, antibiotics, dewormer, and some heart medications can cause diarrhea in dogs).
Stress, excitement, or anxiety, e.g. after boarding at kennels.

Chronic diarrhea can be caused by:

Poor-quality food.
Intestinal parasites.
A compromised immune system.
A weak gastrointestinal system.
Other more serious underlying health issues (such as colitis, inflammatory bowel disease, kidney and liver disease, pancreatitis, or stomach cancer).