Upper gastrointestinal bleeding cannot be caused by colon cancer, as the colon is part of the lower gastrointestinal tract. Therefore, upper gastrointestinal bleeding cannot result from colon cancer. There are several diseases that can cause upper gastrointestinal bleeding: The first common cause is peptic ulcer, including both gastric ulcers and duodenal ulcers, which can lead to bleeding in the upper gastrointestinal tract. The second cause is bleeding due to esophageal or gastric varices rupture associated with liver cirrhosis. This type of bleeding can be substantial and sometimes life-threatening. The third cause is acute gastric mucosal injury, such as that caused by heavy alcohol consumption or the use of nonsteroidal anti-inflammatory drugs (NSAIDs). The fourth cause is gastric cancer, which can lead to upper gastrointestinal tract bleeding. While colon cancer can cause rectal bleeding, it is not a cause of upper gastrointestinal tract bleeding.