Ruptured Sac

• A ruptured anal sac oozes blood as the infection drains, and the area must be cleansed with a towel that has been dipped in a saline solution.
  
  

Colitis

• Colitis causes bloody diarrhea and is treatable with prescription metronidazole. This antibiotic usually eliminates those bouts of loose stools containing mucous and blood.
  
  

Constipation

• Constipation is uncommon in dogs that are fed and walked regularly, but consumption of bones results in difficult-to-pass feces. Because constipation is rare in dogs, blockage could be the culprit behind straining at the stool, so seek immediate medical attention for your dog.
  
  

Trauma

• During a dog fight, a canine will attack his opponent's rear haunches, sometimes leaving open gashes in the anus. Use a half-and-half mixture of hydrogen peroxide and water to clean the area.
  
  

Next Steps

• Many instances of canine rectal bleeding are easily treatable and not serious. Seek the advice of your vet, however, to ensure the good health of your four-legged friend.