This denotes discomfort that accompanies or follows the intake of food. It is usually associated with difficult or painful digestion and may be related to actual failure of some phase of the digestive process.

Symptoms of indigestion are varied – a feeling of fullness or weight in the pit of the stomach; pain either dull and steady or acute and spasmodic, which may follow immediately or occur sometime after eating; nausea, or vomiting, which often relieves the pain or discomfort. Heartburn may appear, accompanied by acid – sour acid liquid thrown into the mouth from the stomach. Flatulence and coated tongue, headache and dizziness may be present. Belching is not necessarily a sign of indigestion.

One group of gastric disturbances is caused by gastritis, dilation of the stomach, ulcers, cancer, gastroptosis (downward displacement of the stomach), and others. Indigestion may result from disorders in organs other than the stomach, such as cirrhosis (a chronic disease of the liver characterized by the replacement of normal tissue with fibrous tissue and the loss of functional liver cells), gallbladder inflammation, appendicitis, nephritis (inflammation of the kidney), peritonitis (inflammation of the membrane which lines the inside of the abdomen and all of the internal organs), heart or lung diseases which may affect the lining of the stomach, tuberculosis and anemia. Certain mental conditions may be the source of indigestion, such as hysteria, neurasthenia (a psychological disorder characterized by chronic fatigue and weakness, loss of memory, and generalized aches and pains, formerly thought to result from exhaustion of the nervous system), or hypochondriasis (The belief and fear of serious illness which lasts for six months, beyond and despite medical reassurance).

Because indigestion may originate from such wide variety of causes, prompt treatment should be found. The doctor will be guided by the symptoms and treatment may vary from bicarbonate of soda to relieve stomach acidity to surgery for ulcers.

Many cases of indigestion are due to emotional disturbances rather than organic diseases or disorder. Worry, nervousness, or frustration over a long period of time may cause constant irritation in the stomach. The person should endeavor to relieve or remove the causes of tension and to adopt a calmer, more relaxed general attitude. Plenty of sleep, relaxation, and special attention to diet are essential for persons with nervous indigestion.
This information was taken from the New Illustrated Medical and Health Encyclopedia.

In nervous indigestion, treatment includes a regimen of diet and eating habits, which help the stomach, heal itself. This often includes the following:

1. Eat meals at regular hours. This helps the stomach secrete its juices at regular times. If meals are delayed, the concentrated acids may irritate the lining of the stomach, which is the first step to an ulcer.
2. Avoid large heavy meals. Small meals at frequent intervals are better than large meals less frequently.
3. Eat slowly and chew the food carefully.
4. Avoid irritating stimulants and greasy foods.
5. Drink a glass of milk between meals. This will help overcome the excess acid in the stomach.
6. Reduce your alcohol intake.
7. Avoid wearing tight clothes or belts around the stomach area.
8. Try to keep your bodyweight in the healthy range.
9. Avoid bending over or lying down after a meal to help prevent your stomach contents being pushed upwards and causing heartburn.
10. If you have heartburn at night, try sleeping with your upper body in a more propped-up position, and avoid eating for two hours before bedtime.