Also known as a bowel obstruction, or blocked bowel, an intestinal blockage is most often caused by a gastrointestinal foreign body (your dog swallowed something he shouldn't have). Other causes may be intussusception - (the bowel folding in on itself), hernias, tumours and adhesions from abdominal surgery.
A partial blockage in the intestines will produce intermittent symptoms, of vomiting, diarrhea, and cramping. A complete blockage will produce severe and sudden abdominal pain, violent, possibly projectile vomiting. The vomited material may consist of fecal-like matter, if the blockage is located in the lower GI tract, along with distention of the abdomen.
If the blockage interferes with the flow of blood to the bowel, intestinal strangulation will occur, and the bowel will start to rot within a few hours. Abdominal x-rays are needed to properly diagnose the cause of distress and locate the blockage. Surgical removal of the blockage is required immediately, and the rotting bowel must be resected to the living bowel.