Constant diareaha. Doctor done a lot of stool, blood, urine samples, +viewed both my stomack and colon with a tube. What does a funcional problem mean?

= A Dx of exclusion. When a GI problem is labelled "functional" it means inflammation, infection, & ischemic pathology, as well as motility disorders have been ruled out. Ruled in are conditions that alter how the gut "senses" pain, distension, & the movement of food or residue. The good news then is that there's no bad news, allowing the symptoms you describe to be addressed without concern for missing a bad problem.