Ulceration of the gastrointestinal tract is a common problem. Ulceration can occur in the esophagus or feeding tube from acid reflux, infection, pills and radiation or chemotherapy. Ulcers can occur in the stomach and duodenum, also known as peptic ulcers. These ulcers are almost always due to either presence of a bacteria infection, Helicobacter pylori, and/or nonsteroidal anti-inflammatory drugs (NSAIDS). NSAIDS include garden variety aspirin, various forms of ibuprofen (Advil, Motrin), naproxen (Aleve) or others such as Celebrex, Indocin.

Ulcers can also occur in the duodenum and further down in the small bowel (jejunum) from Celiac disease.tata Ulcers from NSAIDS also occur in the jejunum, distal small bowel (ileum) or large intestine/bowel known as the colon, or the rectum. Ulcers in the ileum and colon are common in Crohn's disease. Ulcers in colon are common in ulcerative colitis as well can occur in other forms of colon inflammation (colitis) including infections from bacteria and viruses such as cytomegalovirus (CMV). Ulcers look like "canker sores" that some people get in their mouths. In fact some people with chronic intestinal inflammation or inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis, also get mouth canker sores that occur when their intestine is actively inflamed.

The images below depict various forms of ulcers seen in the gastrointestinal tract.