My continous 4-5 times stool passing from 2 week and black yellow mix type stool. what is the problem?

Diarrhea: Loose yellow, frequent stools could be from a viral gastrointestinal tract infection with subsequent irritable bowel. However black stool, if not from taking peptobismol, could indicate bleeding from high in the gi tract from gastritis or a peptic ulcer. I recommend seeing your physician who can perform a simple stool test in the office to check for occult blood. Follow a bland, low roughage diet