Intestinal lining coming out in feces, is that possible?

ProbablyThickMucus: Yes, if you are a fish being gutted. As a human you'd have to be pretty damned sick, with the inner lining of the intestines or colon sloughing off, like with necrotizing enterocolitis or a BAAAD case of ulcerative colitis or-- a piranha eating its way through your gut. In many inflammatory problems, microscopic portions may pass out but not the whole lining!