Okay... I had this problem before... I had cancer
A number of things could cause this. Your dog may have eaten something that caused diarrhea. Contrary to what many people believe, it is not good for dogs to eat 'people' food. Also, your dog could...
you mean "WHAT is jelly mucous stool in puppies?", yes?
This question is best left for your veterinarian, he can give your dog tests to find out what the problem is.