The way in which DEET works is that it prevents the insects from being able to detect the carbon dioxide produced when we breath. DEET does not actually kill the mosquitoes but deters them. DEET repellents can vary in strength from 4 to 100%. The higher the percentage of DEET present in the repellent, the longer that the protection lasts. However studies have shown that using a repellent with a 100% concentration will only give you an extra hour of protection than a repellent with a 50% concentration. Studies have been carried out into the toxicity of DEET on humans but test found that there were no serious detrimental effects. A few side effects, such as skin rashes, occur but that is really to be expected. It seems that the possible problems when one uses DEET is far outweighed by the benefits to repelling mosquitoes and other biting insects.

DEET is available in a number of different forms including liquids, lotions, sprays and impregnated materials. Recent figure suggest that one third of all Americans use DEET every year and it is used throughout the world.

Although DEET is widely accepted as safe there are some simple guide lines that you should follow when using DEET based, or any other, repellents.

When you are in area with a high mosquito population you should wear long sleeves and trousers
You should apply repellent sparingly to exposed skin or clothing
Do not inhale repellents and keep way from eyes
Avoid applying repellents to the hands of children as they may rub their eyes or mouth
Never use repellents on wounds or irritated skin
Women who are breastfeeding should minimise the amount of repellent that they use
If an adverse reaction occurs then wash the repellent off and contact a doctor