Defecation
The passage of bowel contents through the rectum and anus.

Defecography
An x-ray of the anus and rectum to see how the muscles work to move stool. The patient sits on a toilet placed inside the x-ray machine.

Dehydration
Loss of fluids from the body, often caused by diarrhea. May result in loss of important salts and minerals.

Delayed Gastric Emptying
See Gastroparesis.

Dermatitis Herpetiformis
A skin disorder associated with celiac disease. See also Celiac Disease.

Descending Colon
The part of the colon where stool is stored. Located on the left side of the abdomen.

Diaphragm
The muscle wall between the chest and the abdomen. It is the major muscle that the body uses for breathing.

Diarrhea
Frequent, loose, and watery bowel movements. Common causes include gastrointestinal infections, irritable bowel syndrome, medicines, and malabsorption.

Dietitian
An expert in nutrition who helps people plan what and how much food to eat.

Digestants
Medicines that aid or stimulate digestion. An example is a digestive enzyme such as Lactaid for people with lactase deficiency.

Digestion
The process the body uses to break down food into simple substances for energy, growth, and cell repair.

Digestive System
The organs in the body that break down and absorb food. Organs that make up the digestive system are the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus. Organs that help with digestion but are not part of the digestive tract are the tongue, glands in the mouth that make saliva, pancreas, liver, and gallbladder.

Digestive Tract
See Gastrointestinal (GI) Tract.

Distention
Bloating or swelling of the abdomen.

Diverticula
Plural form of diverticulum. See Diverticulum.

Diverticulitis
A condition that occurs when small pouches in the colon (diverticula) become infected or irritated. Also called left-sided appendicitis.

Diverticulosis
A condition that occurs when small pouches (diverticula) push outward through weak spots in the colon.

Diverticulum
A small pouch in the colon. These pouches are not painful or harmful unless they become infected or irritated.

Dry Mouth
See Xerostomia.

Dubin-Johnson Syndrome
An inherited form of chronic jaundice (yellow tint to the skin and eyes) that has no known cause.

Dumping Syndrome
A condition that occurs when food moves too fast from the stomach into the small intestine. Symptoms are nausea, pain, weakness, and sweating. This syndrome most often affects people who have had stomach operations. Also called rapid gastric emptying.

Duodenal Ulcer
An ulcer in the lining of the first part of the small intestine (duodenum).

Duodenitis
An irritation of the first part of the small intestine (duodenum).

Duodenum
(doo-AW-duh-num)
The first part of the small intestine.

Dysentery
An infectious disease of the colon. Symptoms include bloody, mucus-filled diarrhea; abdominal pain; fever; and loss of fluids from the body.

Dyspepsia
See Indigestion.

Dysphagia
Problems in swallowing food or liquid, usually caused by blockage or injury to the esophagus.