Is your dog is pooping blood only without defecation or he is having bloody diarrhea. If he is having bloody diarrhea and vomiting then there are following possibilities.
- Intestinal parasites
- Bacterial, viral, fungal and protozoan infections of GI tract
- Polyps in rectum or colon
- Food allergies
- Dietary intolerance
- Diseases of anus, colon and rectum