• Canine colitis is a condition in which the large intestine becomes inflamed, causing pain and discomfort. There are several causes, including food allergies or intolerances; viral, bacterial or fungal infections; colon cancer; and inflammatory bowel diseases. In some dogs, colitis can be acute and last only a few days or weeks. Some dogs, however, have chronic colitis and are always bothered by it. In many cases, symptoms are mild and may not be noticed until they continue for some time.
  
  

Feces

• Dogs with colitis will often have small amounts of blood in their feces. In some cases, this may be mostly unnoticeable. The feces may also be very mucousy and runnier than normal. Diarrhea and constipation are both common in dogs with colitis, and in some cases it may be painful for the dog to defecate because of the inflammation in the large intestine.
  
  

Vomiting

• Dogs with colitis may also experience frequent and recurrent bouts of vomiting. Even healthy dogs will vomit from time to time. In dogs with colitis, however, the vomiting is more continuous, although she may not vomit several times a day or even every day.
  
  

Weight Loss

• Unexplained weight loss is another sign of canine colitis. Unless dogs are put on a diet or have their exercise regimen increased, they will not generally lose weight unless they are ill or have a medical condition. Weight loss in dogs is often a sign of a potentially serious medical problem, such as colitis, and should be reported to your veterinarian.
  
  

Lethargy

• Dogs with colitis may become lethargic and less active than normal. Although this can be difficult to pick up on in many dogs, it should be reported to your veterinarian because it is often a sign your dog is ill.