Digestive Disorders - Merck Manuals Consumer Version

Health Topics & Chapters

Biology of the Digestive System
The digestive system, which extends from the mouth to the anus, is responsible for receiving food, breaking it down into nutrients (a process called digestion), absorbing the nutrients into the bloodstream, and eliminating the indigestible parts of food from the body. The digestive tract consists of the
Symptoms of Digestive Disorders
Disorders that affect the digestive (gastrointestinal) system are called digestive disorders. Some disorders simultaneously affect several parts of the digestive system, whereas others affect only one part or organ.
Diagnosis of Digestive Disorders
Disorders that affect the digestive (gastrointestinal) system are called digestive disorders. Some disorders simultaneously affect several parts of the digestive system, whereas others affect only one part or organ. (See also Overview of the Digestive System.)
Anal and Rectal Disorders
The anus is the opening at the end of the digestive tract where stool leaves the body.
Bezoars and Foreign Bodies of the Digestive Tract
Bezoars are tightly packed collections of partially digested or undigested material that can become stuck in the stomach or intestines.
- Bezoars
- Foreign Bodies in the Digestive Tract
Diverticular Disease
Diverticular disease is characterized by small, balloon-like sacs (diverticula) protruding through the layers of particular structures in the gastrointestinal tract (digestive tract).
Esophageal and Swallowing Disorders
The esophagus is the hollow tube that leads from the throat (pharynx) to the stomach. Food does not just fall through the esophagus into the stomach. The walls of the esophagus propel food to the stomach by rhythmic waves of muscular contractions called peristalsis.
Gastritis and Peptic Ulcer Disease
Gastritis and peptic ulcer disease involve damage to the lining of the stomach or duodenum (the first segment of the small intestine). These disorders are usually caused by
Gastroenteritis
Gastroenteritis is inflammation of the lining of the stomach and small and large intestines. It is usually caused by infection with a microorganism but can also be caused by ingestion of chemical toxins or drugs.
Gastrointestinal Bleeding
Bleeding may occur anywhere along the digestive (gastrointestinal [GI]) tract, from the mouth to the anus. Blood may be easily seen by the naked eye (overt), or blood may be present in amounts too small to be visible (occult). Occult bleeding is detected only by testing a stool specimen with special chemicals.
- Gastrointestinal Bleeding
- Esophageal Varices
  - Causes
  - Symptoms
  - Diagnosis
  - Treatment
Gastrointestinal Emergencies
Certain gastrointestinal disorders can be life threatening and require emergency treatment. For many people, emergency treatment involves surgery.
Inflammatory Bowel Diseases (IBD)
In inflammatory bowel diseases, the intestine (bowel) becomes inflamed, often causing recurring abdominal pain and diarrhea.
Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome is a disorder of the digestive tract that causes recurring abdominal pain and constipation or diarrhea.
- Irritable Bowel Syndrome (IBS)
  - Causes
  - Symptoms
  - Diagnosis
  - Treatment
  - More Information
Malabsorption
Malabsorption syndrome refers to a number of disorders in which nutrients from food are not absorbed properly in the small intestine.
Pancreatitis
Pancreatitis is inflammation of the pancreas.
Tumors of the Digestive System
Anal cancer develops in the skin cells of the immediate area around the anus or in the lining of the transitional zone between the anus and the rectum (the anal canal). Unlike in the rectum and the large intestine, in which cancers are almost always adenocarcinomas, cancers of the anus are primarily squamous cell carcinomas.