Yes. Recently, safety concerns have been raised about DEET, the most reliable and widely used repellent to prevent insect bites. Some people who have used DEET have complained of allergic rashes, contact dermatitis, and possible neurological side effects, such as seizures and encephalitis. While such reports can be alarming, it's important to put the facts in perspective.

DEET has an outstanding safety profile. This chemical compound (also known as N, N-diethyl metatoluamide or N, N-diethyl-3-methylbenzamide) was patented by the U.S. Army in 1946 and has been sold publicly since 1957. Every year, more than 100 million Americans use a DEET-based insect repellent. Worldwide use exceeds 200 million people per year. Given this extensive use, there have been remarkably few reports of major side effects. From 1961 to 1999, there were fewer than 40 reports of serious adverse events. These problems seem more likely to occur when DEET is applied very frequently or heavily to large areas of the body.

When DEET is used properly, it has an almost complete absence of risk that must be compared to the risk of getting insect-transmitted diseases, such as malaria, yellow fever, and dengue fever. Insects are a very important cause of disease in humans. Mosquitoes transmit infection to more than an estimated 700 million people every year. One in every 17 people alive today will die from mosquito-borne illness.

Repellents are very important in our defense against insect-borne infections, and our only defense against some mosquito-borne diseases, such as dengue fever. Vaccines can cut the risk of other mosquito-borne infections, such as yellow fever or Japanese encephalitis, and drugs can reduce the risk of malaria. However, neither the vaccines or the drugs are 100% effective, so repellents such as DEET remain an important part of the arsenal. DEET is highly effective against a wide range of insects, including mosquitoes, fleas, ticks, sand flies, and other biting flies.

Travelers who are wary of DEET often use bath oil or plant-derived repellents, such as citronella. Although some of these products can decrease mosquito bites, they offer less protection than DEET. To achieve a level of effectiveness similar to that of DEET, some of these products would need to be re-applied every 30-40 minutes. (For example, Avon Skin-So-Soft bath oil provides protection for a period that is only one-tenth as long as that of a 12.5% DEET solution.) Since DEET was invented, more than 20,000 compounds have been tested in an attempt to find a better insect repellent, but none so far have matched DEET in terms of level and duration of protection.

Despite the evidence that supports the safety of DEET, it is important to use common sense and follow the manufacturer's directions carefully. Recommended guidelines for DEET include the following:

· Only apply to exposed skin.

· Do not apply to cuts or abrasions.

· Avoid the eyes and mouth.

· Wash off DEET as soon as the risk of insect bites has passed.

· Use the lowest effective concentration of DEET whenever possible. The U.S. Centers for Disease Control and Prevention recommends using products that contain less than 30-35% DEET. (In general, the only advantage to using a higher concentration of DEET is that it may provide longer-lasting protection.)

· Consider using "controlled release" DEET products for additional safety.

· Limit exposure to DEET in babies and small children.