Blood in stool can be due to many reasons but usually not due to gallbladder problem. Bloody stool can be due to hemorrhoids, infection in colon and stomach, and ulcer. Gallbladder symptoms are pain in upper abdomen, nausea, vomiting, bloating, fever, indigestion, jaundice, clay colored stool etc. If you are having bloody stools then visit a doctor for proper diagnosis and treatment.