Indigestion has many possible causes. Often, indigestion is related to lifestyle and may be triggered by food, drink or medication. Common causes of indigestion include:

• Overeating or eating too quickly
• Fatty, greasy or spicy foods
• Too much caffeine, alcohol, chocolate or carbonated beverages
• Smoking
• Anxiety
• Certain antibiotics, pain relievers and iron supplements

Sometimes indigestion is caused by other digestive conditions, including:

• Gastritis
• Peptic ulcers
• Celiac disease
• Gallstones
• Constipation
• Pancreas inflammation (pancreatitis)
• Stomach cancer
• Intestinal blockage
• Reduced blood flow in the intestine (intestinal ischemia)
• Helicobacter pylori (H. pylori) infection
• Small intestinal bacterial overgrowth
• Gastroparesis

Indigestion with no obvious cause is known as functional or no ulcer dyspepsia.
 

• Fullness during a meal. The person feels overly full soon after the meal starts and cannot finish the meal.
• Bothersome fullness after a meal. The person feels overly full after a meal—it may feel like the food is staying in the stomach too long.
• Epigastric pain. The epigastric area is between the lower end of the chest bone and the navel. The person may experience epigastric pain ranging from mild to severe.
• Epigastric burning. The person feels an unpleasant sensation of heat in the epigastric area.

Other, less frequent symptoms that may occur with indigestion are nausea and bloating—an unpleasant tightness in the stomach. Nausea and bloating could be due to causes other than indigestion.

• Sometimes the term indigestion is used to describe the symptom of heartburn, but these are two different conditions. Heartburn is a painful, burning feeling in the chest that radiates toward the neck or back. Heartburn is caused by stomach acid rising into the esophagus, causing a symptom of gastroesophageal reflux disease (GERD). A person can have symptoms of both indigestion and heartburn.

The doctor may perform blood, breath, or stool tests if the type of bacteria that causes peptic ulcer disease is suspected as the cause of indigestion.

The doctor may perform an upper endoscopy, and may perform biopsies—removing small pieces of tissue for examination with a microscope—to look for possible damage from gastroesophageal reflux disease (GERD), infection, or evidence of food allergy.
 

Lifestyle changes may help ease indigestion. Your doctor may recommend:

• Avoiding foods that trigger indigestion
• Eating five or six small meals a day instead of three large meals
• Reducing or eliminating the use of alcohol and caffeine
• Avoiding certain pain relievers, such as aspirin, ibuprofen, and naproxen sodium
• Finding alternatives for medications that trigger indigestion
• Controlling stress and anxiety

If your indigestion persists, medications may help. Over-the-counter antacids are generally the first choice. Other options include:

• Antacids - are usually the first drugs recommended to relieve symptoms of indigestion.
• Histamine-2 receptor antagonists (H₂RAs) - reducing stomach acid. They work longer than but not as quickly as antacids.
• Proton pump inhibitors (PPIs) - are most effective in treating symptoms of indigestion in people who also have gastroesophageal reflux disease (GERD). Prokinetics may be helpful for people who have a problem with the stomach emptying too slowly, and also improves muscle action in the digestive tract. Prokinetics have frequent side effects that limit their usefulness, including fatigue, sleepiness, depression, anxiety, and involuntary muscle spasms or movements.

Although indigestion doesn't usually have serious complications, it can affect your quality of life by making you feel uncomfortable and causing you to eat less. You might miss work or school because of your symptoms. When indigestion is caused by an underlying condition, that condition can also have its own complications.