“Peptic ulcers are open sores that develop in the lining of the stomach, esophagus and small intestine due to an imbalance between hydrochloric acid and pepsin. These acidic digestive juices are secreted by the cells of the stomach. Named for where they are found, "peptic ulcers are a very common and often recurring health problem, and it is estimated that more than 20 million Americans will suffer from a peptic ulcer in their lifetime." (Cleveland). Gastric ulcers occur inside the stomach. These are often the result of the bacteria Heliobacter pylori (H. pylori), which causes stomach infection, inflammation and cancer. Heliobacter pylori produces toxic molecules that weaken the stomach's protective mucus, making it more susceptible to the damaging effects of stomach acids and thus producing more acid. According to MedlinePlus, researchers believe it could be spread through unclean food and water, since it is found in about two-thirds of the world's population. Esophageal ulcers are found inside the stomach lining. They occur in the hollow muscular tube called the esophagus, which carries food from the throat to the stomach. In severe cases, when there is a reflux of gastric juice through the cardiac sphincter, it can ultimately become perforated and cause serious inflammation of the tissues surrounding it, the heart and the tissues between the lungs. Duodenal ulcers are the most common and occur on the inside of the upper part of the small intestine called the duodenum. This occurs when acidic chyme, a semi-fluid mass of partially digested food, is expelled through the stomach into the duodenum. This chime is not completely neutralized when it enters through the pyloric sphincter, thus producing erosions middle of paper...... Tick ulcer: causes, treatment and prevention. "Trusted medical information and health advice: Healthline. Healthline Networks, August 15, 2012. Web. January 27, 2014. Marks, Jay W. "Symptoms, causes, treatment of peptic ulcer disease?" MedicineNet, nd Web. "Definition of Peptic Ulcer - Diseases and Conditions - Mayo Clinic." Mayo Clinic for Medical Education and Research, July 16, 2013. Web, January 27, 2014. "Peptic Ulcer: MedlinePlus -. National Institutes of Health. NIH: National Institute of Diabetes and Digestive and Kidney Diseases, January 5, 2014. Web January 27, 2014. Rigas, Basil, Chris Feretis and Efstathios D. Papavassiliou “John Lykoudis: An unsung discoverer of. the cause and treatment of peptic ulcer. "The Lancet 354.9190 (1999): 1634-5. ProQuest. Web. January 26. 2014.