As the name suggests, 'Gastrointestinal bleeding' is the bleeding in the gastrointestinal tract, no matter where from the mouth to the rectum. Vomiting red/black blood, red/black stool, shortness of breath, abdominal pain, pale skin, or passing out are the visible symptoms of this condition. Peptic ulcer, esophageal varices and cancer cause upper GI (gastrointestinal) bleeding. Whereas, lower GI bleeding is caused due to hemorrhoids, cancer, and inflammatory bowel disease, etc. It can be diagnosed by endoscopy, medical imaging and fecal occult blood test.