Becky Moody, age 14, of Meridian, miss., for her question:

HOW DO DOCTORS TREAT DIVERTICULITIS?I

Diverticulitis is a common disease of the large intestine or colon. Doctors treat it with antibiotics to control infection, drugs to relax the muscles of the colon and compounds to help empty the colon.

Diverticulitis develops from diverticulosis, a disorder that is widespread among middle aged and elderly people in North America and northern Europe.

Diverticulosis involves the presence of pouches called diverticula along the outside of the colon. A single pouch is called a diverticulum. Diverticula rarely form in people under the age of 30. Most diverticulosis patients have no symptoms.

Doctors for many years thought that diverticulosis, or the development of the pouches, was caused by a diet too high in roughage, or fruit and vegetable fibers. But today there is evidence to show just the opposite. People are better off with a diet high in roughage.

A diet in which there is a shortage of roughage, doctors have determined, makes the waste material in the colon extremely firm and compact. The waste cannot move easily through the colon and high pressure results.

Pressure in the colon can force the inner membrane of the colon to bulge out through several weak points in the lining of the organ. Such action forms small, permanent diverticula that may be seen with an X ray examination.

In the United States, where most people eat relatively little roughage, nearly half of those over the age of 60 have diverticulosis. The condition rarely occurs in underdeveloped countries, where the standard diet has a high fiber content.

Diverticulitis develops in many cases of diverticulosis. It results when one of the diverticula breaks open. The material that leaks out infects the outer surface of the colon. In most cases, the infection stays in a small area. But it may spread and develop into peritonitis.

Peritonitis is an inflammation of the peritoneum, the thin membrane that lines the abdominal cavity. It .is a serious illness that can cause death.

Peritonitis requires prompt medical care. Antibiotics and other drugs are used to treat any infection and control pain.

The colon is divided into four sections. The ascending colon extends upward on the right side of the abdominal cavity. It jouns the transverse colon, which extends across the cavity to the opposite side. This section meets the descending colon which passes down the left side to join the S shaped sigmoid colon.

In human beings, the colon is about five feet long. It removes water and mineral salts from the chyme, or food residue. Its strong muscles contract and relax to push the residue toward the rectum.

Mucus covers the colon's inner surfaces to lubricate them and ease the passage of chyme.