Tales of your recent travels may bore your friends and family, but don't think the same of your physician.

You should always tell your doctors all the places -- whether in this country or abroad -- you have recently visited, no matter the nature of your illness or how trivial it seems.

In a sense, physicians are detectives. The more clues they have about an illness, the sooner they will solve the case. According to the American Society of Internal Medicine, 70 percent of correct medical diagnosis by physicians depends solely on what their patients tell them.

It is important to realize that many illnesses are geographical -- including intestinal disorders, skin conditions and upper respiratory infections. In other words, an illness that you contract overseas, in another part of this country or even in a rural park an hour's drive from home may not exist where you live.

If you don't mention your travels, your doctor may spend a great deal of time ruling out local illnesses before discovering your possible exposure to other diseases. In addition, some of the illnesses you contract away from home do not show symptoms until weeks later, a time when your trip is not in the forefront of your mind.

Most troublesome are illnesses contracted overseas or in a distant part of this country. Take malaria, for example. According to the World Health Organization, it is one of the most common infectious diseases in the world, with perhaps a billion cases worldwide. But since it exists in the tropics and subtropics, the only cases seen in this country are in travelers who come home with it.

Your physician may have problems making a prompt diagnosis of malaria, for several reasons:

Very few doctors have ever seen a case.

Malaria is a great imitator, giving the same symptoms as many local, everyday conditions.

Unless doctors ask for special studies, even laboratory tests may miss the diagnosis.

Unfortunately, malaria responds only to very specific medications, and delaying treatment worsens the disease. Reporting a visit to tropical areas to your doctor can be an important factor in diagnosing malaria.

Some illnesses are even localized to specific areas of North America: fungal infections in the deserts of Arizona and California, swimmers' itch from swimming in the lakes of the north-central United States and central Canada, neurological and intestinal conditions from eating fish in the Caribbean, intestinal infection due to drinking unsterilized water from streams and lakes in the western United States and Canada.

On the other hand, even when your condition is obvious and your physician makes a prompt diagnosis, it is still important to give your doctor your travel history. After all, certain illnesses -- including sexually transmitted diseases and certain skin infections that are contracted in the Middle East or Southeast Asia -- require different antibiotics than the same condition contracted locally.

If there is a chance that your illness may have been contracted outside your immediate home area and the illness is not responding to conventional treatment, discuss with your physician whether or not you should consult a specialist in travel medicine or infectious diseases. Such specialists are far more likely to be familiar with exotic and tropical diseases. You can find one in most large medical centers.

Also, keep in mind that objects you have brought back with you from overseas can cause health problems. For example, some earthen jars from Mexico are high in lead content. Hot liquids placed in the jar leach out some of the lead and you ingest the lead when you drink the liquid. And goat-skin products from Haiti, which may be sold in other areas of the Caribbean, may contain anthrax organisms, which can cause skin and lung problems. Anthrax spores are highly resistant to disinfectants and the spores may remain viable for years. Dr. Karl Neumann is a pediatrician in Forest Hills, N.Y., who writes about travel and health.