Jim Greene, age 14, of San Antonio, Tex., for his question:

WHAT CAUSES HEARTBURN?

Heartburn is a burning sensation in the esophagus that seems to start just below the tip of the breastbone and rises toward the mouth. It is associated most often with bad eating habits.

Heartburn most frequently happens after drinking hot or cold liquids. It may occur after eating while tense or tired. Heartburn may also be caused by emotional problems.

Sometimes heartburn is a symptom of esophageal disease, especially if there is regurgitation of the stomach contents into the esophagus.

Heartburn also occurs in connection with peptic ulcer or gallbladder disease.

Some doctors believe that heartburn is the result of an intense spasm of the esophagus, which may or may not be related to an organic disease.

The pain of heartburn, also called pyrosis, may last for several hours.