It has long been known that the most effective repellents are those which contain DEET. DEET is the abbreviation for the chemical N,N-diethyl-meta-toluarnide. DEET has been sold in the United States since 1956 and is used by 50 to100 million people each year. It repels mosquitoes, no-see-ums, fleas, ticks, gnats, horse flies, deer flies, yellow flies, and chiggers. Repellents containing DEET are available as pump sprays, aerosols, lotions, creams, soaps, and sticks. In general, inexpensive products contain less than 10% DEET, while the more expensive ones are at least 20% DEET. There are over 40 products containing from 5% to 95% DEET which can be purchased. Products with more than 35% DEET are available, most often, through camping and outdoor supply stores. If a little DEET is good, is a lot of DEET better? Not necessarily. In tests done by the army, repellents with 30 to 40%DEET worked twice as well as repellents with 75% DEET. Read the label and check to see what percentage of the product is DEET. This information is found under active ingredients. The label may say DEET, or it may spell out the chemical name. Some people need to use higher concentrations, while a lesser concentration may suffice for others. It is always best to use the lowest concentration that is effective. People should check to see if it is a controlled release formula (long-lasting) and compare the amount of product and the type of application. Lotions provide the most even coverage. Sprays are more convenient but require greater care in applying. The entire label should be read before choosing what is best for a family.