An ulcer is a sore that is found in the lining of the gastrointestinal or GI tract. Your sore is found in the upper part of the small bowel. This is called the duodenum and is where the stomach ends. Doctors call this a duodenal ulcer. A germ called Helicobacter pylori often causes these ulcers. These germs hurt the protective lining. Then the stomach acid gets through to the lining. The acid is so strong that it causes a sore or hole in the lining of the GI tract. There are also other causes of ulcers. Some of them are the use of aspirin, ibuprofen and nonsteroidal anti-inflammatory drugs (NSAIDs), or lots of acid as seen in Zollinger-Ellison syndrome. Ulcers may be treated and managed by drugs and changes to your way of life. The doctor may suggest surgery in cases of bad ulcers.