DEET, the chemical name of DEET, is a broad-spectrum insect repellent. It can repel a variety of human biting insects in various environments. It can repel thorn flies, midges, black flies, Chigger Mites, deer flies, fleas, Simulium, horseflies, mosquitoes, sand flies, small flies, barn flies and ticks. DEET was developed and patented by the U.S. Department of agriculture during World War II. The product was designated as a mosquito repellent product for the U.S. Army in 1946. In 1957, it was registered as an insect repellent by the U.S. Environmental Protection Agency. It was first used as an insecticide on farms. Later, the U.S. government applied for its use in wartime, especially in Vietnam and Southeast Asia. According to the statistics of the U.S. Environmental Protection Agency, nearly 40% of Americans use insect repellent containing DEET every year, which has been used by about 200 million people around the world for more than 40 years, Studies by more than 20000 research units have proved that DEET is the safest and most effective broad-spectrum repellent on the market. The World Health Organization also recommends the use of repellent products containing DEET to prevent the invasion of disease vectors. It is often mixed with other insecticides, but its toxicity will increase when mixed with carbamate insecticides.