Digestive System Problems

Digestive System

Most common digestive problems cause short-term symptoms, such as indigestion, diarrhoea, and constipation. However, long-term symptoms affecting the digestive system may reflect a more serious underlying disorder.

The first part of this section looks at indigestion, the upper abdominal discomfort that most people feel at some time. Occasionally, as is described in the second article, discomfort may be more vague and persist without an identifiable cause, in which case it is known as nonulcer dyspepsia.

The next articles cover diarrhoea and constipation. These problems often clear up on their own. If they persist, you should seek medical advice because there may be an underlying disorder that needs treatment. Diarrhoea may be a result of gastroenteritis or food poisoning, both of which can be serious in elderly people and young children.

Bleeding from the digestive tract can indicate a serious disorder and is discussed in the next article. New techniques developed in the last 30 years have enabled most cases of digestive tract bleeding to be diagnosed and treated without the need for surgery.

The final articles look at nutritional deficiencies, which are rare in the UK, and obesity, which affects about a quarter of the UK’s adult population.

Key anatomy

For more information on the structure and function of the digestive system, see Digestive System.


Nonulcer Dyspepsia




Food Poisoning

Bleeding from the Digestive Tract

Nutritional Deficiencies

Obesity in Adults

Digestion begins in the mouth, where food is chewed by the teeth and mixed by the tongue with saliva secreted by the salivary glands. Swallowing forces the food into the oesophagus, where it progresses to the stomach by coordinated muscle contractions. The mouth, tongue, and oesophagus are constantly exposed to irritants and infection from food and airborne particles.

The first half of this section deals with disorders of the mouth and tongue. These conditions range from mouth ulcers, which are common and relatively mild, to the serious disease mouth cancer. Also included are disorders that involve inflammation, such as glossitis (inflammation of the tongue), and disorders that cause white patches in the mouth, such as oral leukoplakia.

Two disorders affecting the salivary glands are described next. Salivary gland stones are painful but can usually be removed successfully. The majority of salivary gland tumours are not cancerous, and their outlook is generally good, but they may recur.

The last part of the section covers disorders of the oesophagus, including gastro-oesophageal reflux disease, which is the most common, and cancer of the oesophagus.

For disorders specifically affecting the teeth and gums, see Teeth and Gums.

Key anatomy

For more information concerning the structure and function of the mouth, tongue, and oesophagus, see Digestive System.

Mouth Ulcers



Oral Lichen Planus

Oral Leukoplakia

Mouth Cancer

Salivary Gland Stones

Salivary Gland Tumours

Gastro-oesophageal Reflux Disease


Cancer of the Oesophagus

The stomach and the duodenum (the first part of the intestine) are exposed to many potentially damaging substances, including acid produced by the stomach to aid food digestion, alcohol, and irritant foods such as spices. The stomach and duodenum have a natural defence mechanism that protects against damage, but sometimes this mechanism fails, leading to disease.

The first article in this section covers infection with the Helicobacter pylori bacterium, which was discovered in the early 1980s. It is now estimated that about half the world’s population is infected with H. pylori. In most cases, there are no symptoms. However, H. pylori is known to be associated with the disorders of the stomach and duodenum discussed in this section: gastritis, which is inflammation of the lining of the stomach; peptic ulcer, which is an area of the stomach lining or the duodenum that has been eroded by acidic digestive juices; and stomach cancer. Both gastritis and peptic ulcer are common disorders of the digestive system that affect thousands of people in the UK every year. However, if either of these disorders occurs with H. pylori infection, it can usually be treated with drugs. The final article covers stomach cancer, which is now rare in many developed countries. General problems that may involve the stomach or another part of the upper digestive tract are covered elsewhere (see Indigestion; Nonulcer dyspepsia; and Gastro-oesophageal reflux disease).

Key anatomy

For further information about the structure and function of the stomach and duodenum, see Digestive System.

Helicobacter Pylori Infection


Peptic Ulcer

Stomach Cancer

One of the main functions of the liver and pancreas is to aid food digestion. The liver makes the digestive fluid bile, which is stored in the gallbladder. The pancreas makes digestive enzymes. These organs have other vital functions. The liver uses digestion products to make new substances such as proteins and fats, and the pancreas produces hormones that control the level of glucose in the blood.

The yellow discoloration of the skin and eyes known as jaundice is a sign of liver disease but also has other causes, which are discussed in the first article in this section. The next two articles cover hepatitis due to viral infection, which is the most common cause of liver disease worldwide, as well as other forms of hepatitis. Excessive alcohol consumption is the main cause of liver disease in Western countries; three articles deal with alcoholic liver disease and its complications – cirrhosis and portal hypertension and varices. Liver cancer is then described; the first type, which originates in the liver, is less common in Western countries than cancer that spreads from other organs to the liver (liver metastases). Liver failure, which may be fatal unless treated with liver transplantation, is also discussed.

Gallstones do not usually cause symptoms and may not need to be treated, as explained in the next articles, but can lead to inflammation of the gallbladder, called cholecystitis. Articles on the inflammatory conditions, acute and chronic pancreatitis follow, and the final article covers pancreatic cancer, which is relatively uncommon in the UK.

Key anatomy

For information on the structure and function of the liver, gallbladder, and pancreas, see Digestive System.


Acute Hepatitis

Chronic Hepatitis

Alcohol-related Liver Disease


Portal Hypertension and Varices

Liver Cancer

Liver Metastases

Liver Failure



Acute Pancreatitis

Chronic Pancreatitis

Pancreatic Cancer

The intestines, rectum, and anus are exposed to infectious agents and toxins in food, and disorders resulting from these factors are common. Disorders may also be linked to diet, but in many other cases the cause is unknown. Many problems cause changes in the consistency of faeces and in the frequency of bowel movements.

The first article in this section covers irritable bowel syndrome, an extremely common disorder affecting about 2 in 10 people. Disorders that affect the body’s ability to absorb nutrients from food, such as malabsorption and lactose intolerance are described next. Two subsequent articles deal with the inflammatory bowel disorders Crohn’s disease and ulcerative colitis. Digestive disorders that can affect the movement of the intestinal contents, such as hernias, are then discussed. The section also covers appendicitis and colorectal cancer, a common cause of death due to cancer in the UK. Disorders of the rectum and anus are described last.

Articles on diarrhoea and constipation can be found in the section that deals with general digestive and nutritional problems. Intestinal infections (see Infections and infestations) and intestinal disorders in children (see Infancy and childhood) are also covered elsewhere in the guide.

Key anatomy

For further information on the structure and function of the intestines, rectum, and anus, see Digestive System.

Irritable Bowel Syndrome


Food Intolerance

Lactose Intolerance

Coeliac Disease

Crohn’s Disease

Ulcerative Colitis

Polyps in the Colon


Intestinal Obstruction

Diverticular Disease



Colorectal Cancer


Rectal Prolapse


Anal Abscess

Anal Fissure

Anal Itching

Anal Cancer

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

Back to top