Causes

The integrity of the upper gastrointestinal tract is dependent upon the balance between "hostile" factors that can damage the mucous lining (mucosa) of the stomach and upper part of the small intestine (duodenum), such as stomach acid, and "protective" factors, such as hormonelike prostaglandins and mucus. When the effects of hostile factors overwhelm the natural defenses of the mucosa, ulcers form.

Choose another disease or condition... Allergic Rhinitis Allergies, Food Allergy & Asthma Center Alzheimer's Disease Anxiety Aortic Aneurysms Arrhythmia Arthritis, Osteo- (OA) Arthritis, Rheumatoid (RA) Asthma Atopic Dermatitis Attention Deficit Hyperactivity Disorder (ADHD) Back Pain Brain Tumor Bones, Joints & Muscles Center Breast Cancer Brain & Behavior Center Brain Tumor Cancer Center    Brain Tumor    Breast Cancer    Cancer Prevention    Clinical Trials    Colorectal Cancer    Endometrial Cancer    Living With and Beyond Cancer    Lung Cancer    Prostate Cancer    Skin Cancer Cardiomyopathy Cataracts Cholesterol Control Clinical Trials Chronic Obstructive Pulmonary Disease (COPD) Colorectal Cancer Congenital Heart Disease Congestive Heart Failure (CHF) Coronary Artery Disease (CAD) Crohn's Disease Depression Diabetes Center Diabetes, Type 1 Diabetes, Type 2 Digestive Disorders Center Eczema Endometrial Cancer Erectile Dysfunction (ED) Eye & Vision Center Fibroids Fibromyalgia Food Allergies Gallstone Disease Gastroesophageal Reflux Disease (GERD) GERD Glaucoma Hay Fever Headache Heart Center High Blood Pressure Hypertension Hypertrophic Cardiomyopathy (HCM) Impotence Insomnia Irritable Bowel Syndrome (IBS) Living With and Beyond Cancer Losing Weight Lung Cancer Macular Degeneration Memory Loss Osteoarthritis (OA) Osteoporosis Parkinson's Disease Peptic Ulcer Prediabetes Prostate Cancer Respiratory Disorders Center Restless Legs Syndrome (RLS) Rheumatoid Arthritis (RA) Sexual & Reproductive Health Center Sinusitis Skin Cancer Sleep Apnea Sleep Center Stroke Type 1 Diabetes Type 2 Diabetes Ulcerative Colitis (UC) Weight Control See the top six websites for information about peptic ulcers More about digestive health Brain Tumor-Related Clinical Trials Information U.S. News's Health & Wellness Support Networks Email this page Print this section

For many years, doctors believed that an overabundance of stomach acid due to food, alcohol, stress, or other environmental factors was the cause of ulcers. Indeed, the corrosive actions of pepsin (secreted by the mucosa to break down protein) and hydrochloric acid (released in the digestive process) are significant contributors to ulcer formation.

But the key cause of most ulcers is now believed to be infection with a common bacterium called Helicobacter pylori or H. pylori. Although the mechanism by which H. pylori leads to ulcers is not fully understood, scientists believe the bacterium causes chronic inflammation of the stomach or duodenum, which, in turn, weakens the mucosa, allowing acid to cause a sore, or ulcer, in the lining. Once an individual has been infected with H. pylori, the infection continues indefinitely until it is eradicated with antibiotics. Scientists are not yet sure how H. pylori is spread, but it may be through contaminated food or water or person-to-person contact. In the United States, an estimated 30 percent of the population is colonized with H. pylori; 1 in 6 will develop ulcers.

This section also discusses other contributors to ulcer formation.