Daniel Cox, age 15, of Wilmington, Del., for his question:

WHAT CAUSES A STOMACH ULCER?

A stomach ulcer, called a peptic ulcer, is an open sore in the lining of the stomach. Some of the causes or conditions that may lead to such an ulcer include heredity, nervous strain, poor circulation or bad diet.

Too much gastric juice is considered the real cause of stomach ulcers. Excess acid in the stomach keeps the ulcer from healing and keeps it chronic. Ulcers of this type usually cause pain or distress in the pit of the stomach.

Stomach ulcers may sometimes bleed, and they are most dangerous when they perforate or eat through the stomach wall completely. This may lead to peritonitis, an inflammation of the membrane that lines the abdominal cavity.

Stomach ulcers are treated with alkaline drugs and careful diet. Some ulcers require surgery.