Is anal fissure cause Gasto intestine bleeding? I have anal fissure in one year now. I take sitz bath and fissure will cure. I notice small Little Red colours in my stool, in one or two areas of stool. Is this serious matter? And last day onwards my one or two stool colour is brown and Little Black. Is this any serious problem? Not tarry black colour. I don't have stomach pain or nothing like vomiting,nausea or nothing.