If the brown strings are also gel-like this could be mucous that has picked up a bit of fecal material or it could also be blood. Bright red blood usually indicates that any bleeding is coming from somewhere very near the end of the colon...rectum or anus. But if bleeding is occuring farther into the intestines the blood is generally darker...brown or sometimes black. Blood and mucous do not necessarily have to be accompanied by fecal material, although they can be.