Please let us know what happened. My dog who was ten years old recently passed away and I found heavy mucous and blood in her stool around her bedding area. I presumed it was from acute renal failure which is very serious.
Good Lord YES!! You have a medical emergency on your hands. Get that dog to the vet NOW!
I would take you dog into your vet . Call them and let them know what is going on and tell them you are bringing your dog in NOW!! You really don't want to even mess around with blood iN his/her stools. It could be anything from just a tear in the anal wall to some sort of problem in the stomach. Either way a forum is not where you should be ; A vets office is.
I truely hope your dog is ok and that it is nothing to worry about.