I’ll be the first to admit that I stand outside watching each and every performance of my dogs’ “poop show.” This isn’t just a weird sort of voyeurism—rather, it’s a good way to know what’s going on with a dog’s health. If you, too, like to see what’s coming off the production line, keep in mind that the number-one rule of thumb when considering canine elimination is reproducibility. Stools should generally have the same color, size and consistency each and every time.
Many things can cause variations in a dog’s stool. Some of the more common are dietary indiscretions (“garbage gut”) or a change in diet, stress (known as stress colitis), infectious disease, inflammatory conditions, or obstructive processes. Or it may be idiopathic (meaning, we just don’t know what causes it).
A couple of episodes of diarrhea generally don’t constitute an emergency. However, there are situations that do warrant an urgent evaluation. When your dog refuses food or water, vomits, or acts ill or “off,” a trip to the vet is indicated.
Your vet may ask you to bring in a stool sample for analysis. A tablespoon is generally plenty. Also, freshness counts; fecal samples less than an hour old give the best results. If you’re not able to collect one this quickly, get a morning sample, double (or triple!) bag it and keep it refrigerated until your dog’s appointment.
Testing usually starts with a screen for giardia and “O & P,” specifically looking for giardia protozoa as well as ova (eggs) and parasites. During this evaluation, the laboratory technician will also check for overgrowth of normal gastrointestinal (GI) bacteria, which we refer to as clostridial overgrowth. If your dog is acting ill, in addition to having diarrhea, other diagnostics such as blood work and radiographs may be indicated.
1. Streaks of bright red blood and/or mucus on the surface of a mostly normal, formed stool. This is generally caused by inflammation in the large intestine, where mucus is secreted to help protect the intestinal lining. While this does not necessarily indicate an emergency, it’s a good idea to keep a close eye out for further changes in your dog’s behavior and stool.
2. Soft-formed to liquid brown diarrhea, with or without streaks of blood. “Cow patty” and “soft-serve ice cream” are two frequent descriptors. As with the previous type, it is generally not life-threatening as long as there are no other signs of concern and it begins to improve within 24 to 48 hours. If your dog is acting normally otherwise— eating well, not vomiting, good attitude —a wait-and-see home approach may be tried (more on this to follow). Here again, red blood indicates inflammation and bleeding in the colon but does not necessarily mean that your pet is bleeding internally, as is often thought. This is a step up in concern from the previous condition, in the sense that the stool is now softer.
3. A large volume of bloody, watery, diarrhea. This one does require immediate evaluation by your veterinarian, especially with smaller dogs, as it can be an indicator of a common condition called hemorrhagic gastroenteritis, or HGE. (Read more about it here: thebark.com/hge) Tissue sloughing from the intestines gives it a distinctive appearance, and it’s often described as “raspberry jam” diarrhea.
4. Black, tarry stools. This generally indicates bleeding somewhere higher up in the GI tract, such as the stomach or small intestine, and also requires an urgent trip to the vet. A bleeding ulcer (oftentimes caused by steroid or NSAID use) or more generalized bleeding, such as from rat poison, heat stroke or an immune-mediated disease, can display as black, tarry stools. The appearance of the stool is due to the presence of digested blood, and can indicate that a large amount of blood is being lost. In these cases, I usually recommend blood work and an ultrasound to better assess the lining of the intestinal tract.
5. Yellow-orange or pasty, light stools. This may indicate the development of liver or biliary disease, or a too-rapid transit through the small intestine to the colon. A more thorough examination, including diagnostic tests, is in order.
6. Grey, greasy stools. A possible indicator of inadequate digestion and malabsorption of nutrients from the small intestine, this type of stool is typical of exocrine pancreatic insufficiency (EPI), also called maldigestion, a disease in which the pancreas no longer functions as it should. The pancreas is responsible for producing digestive enzymes, and without them, nutrients cannot be properly absorbed. Both German Shepherds and Rough-Coated Collies are commonly afflicted with EPI
7. Green stools. In the ER, I have seen dogs with green stool, and upon examination of the fecal contents, have discovered the cause to be undigested rat bait mixed in with normal stool. This condition also calls for an immediate trip to your veterinarian. Although relatively uncommon, rat poison can also cause both bright blood and dark, tarry stool, so—whether or not you think your dog could have had access to them—please let your veterinarian know if there is any possibility of exposure to rodenticides.
8. Worms. Most of the time, you will not actually see worms in the stool. We typically diagnose worms by looking for their eggs under the microscope; we can tell what type of parasite is present by the shape of the eggs. Occasionally, however, you may see white spaghetti-like shapes (typically, roundworms) in the stool, particularly with puppies. You may also see small flat worms on the outside of the stool or rectum, or “dried rice” in your dog’s sleeping areas. This typically indicates tapeworms, which can take over when fleas are allowed to flourish. Although seeing worms in the stool is not an emergency, an appointment with your vet is in order so you can get medication appropriate for the type of parasite present.
Illustration by Natalya Zahn