Final answer:
Lower GI bleeding can come from ulcers, hemorrhoids, gastritis, colorectal cancer, or inflammatory bowel diseases like ulcerative colitis, with symptoms ranging from rectal bleeding to abdominal pain and bloody diarrhea.
Step-by-step explanation:
Lower gastrointestinal (GI) bleeding can result from conditions such as ulcers, hemorrhoids, gastritis (inflammation of the stomach), and colorectal cancer. Medications like aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) can cause ulcers and gastritis, leading to bleeding. Colorectal cancer may present with symptoms such as rectal bleeding, which can be either visible or occult (hidden in feces). Conditions like ulcerative colitis, which is an inflammatory bowel disease causing inflammation and ulcers in the colon and rectum, can also lead to lower GI bleeding and may produce symptoms like lower abdominal pain and bloody diarrhea.