What are the causes of bloody diarrhoea in puppies?

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Bloody diarrhoea in puppies can be caused by a number of ailments, from food poisoning to internal parasitic infections. Determining a diagnosis often involves blood work and examination of the bloody faeces under a microscope. Puppies have very sensitive immune systems, and veterinary care must be sought immediately to prevent death. Treatment will depend on what is causing the bloody diarrhoea.


A highly contagious disease, canine parvovirus most often afflicts puppies under the age of 6 months. The disease is spread by contact with infected faeces, according to peteducation.com, and is prevalent in kennel situations. Symptoms include dark or bloody diarrhoea, vomiting and lowered white blood cell counts. Treatment requires intensive rehydration and intravenous drug therapy. Parvo rapidly attacks the immature immune system of puppies and many cases results in death.


The same household items that can poison a child can poison a puppy, including lead-based paint, bathroom cleaning products, antifreeze, insecticides and certain kinds of aspirin. Common symptoms of poisoning may include bloody diarrhoea, vomiting, lethargy, lack of appetite, staggering, and difficulty breathing, according to Dogs-Central.com. Antifreeze is particularly lethal, causing kidney failure in a matter of days after ingestion.

Foreign object

Puppies are extremely curious and need to be closely monitored to prevent the ingestion of foreign objects, such as sticks or chicken bones. These items can cause damage to the digestive tract as they splinter and work their way down through the intestinal tract or as the puppy vomits. Bloody diarrhoea always accompanies digestive tract irritations, and the colour of the blood can help your vet determine whether the damage is in the large or small intestine or the stomach.


Puppies can contract bacterial infections from ingesting contaminated and spoiled food or dirty drinking water. Certain harmful strains of the E. coli bacteria travel quickly through the small intestine, causing severe bloody diarrhoea and rapid dehydration, which can quickly prove fatal to a puppy. Salmonella bacteria also causes bloody diarrhoea and, like parvovirus, is contagious. Clostridium is a group of bacteria that also attacks the intestinal tract of puppies, causing bloody diarrhoea.


Parasitic infestation in the form of worms is a common disease in puppies. Some of the more prevalent worms include roundworms, tapeworms whipworms, hookworms and heartworms. The worms are most commonly transmitted to the puppy by its mother or by fleas, contaminated food and faeces and mosquitoes, respectively. In addition to blood, the puppy will pass the worms through bloody diarrhoea. Deworming medications can also exacerbate the bloody diarrhoea temporarily.

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