In hot summer, some cool spray that "spray can make you feel cool" are hot. Lun Wenhui, chief physician of the dermatology and venereology department of Beijing Ditan Hospital, reminded that the cooling spray should not be directly sprayed on the skin surface to prevent skin frostbite or allergy. In a convenience store, there are three rows of "cool spray" with different fragrance types on the shelf. How to use it: The cooling spray should be 5 to 10 cm away from the human body, aimed at the hot part, and sprayed several times through clothes to cool down. "This cool spray is very popular, and can sell more than 10 bottles a day," said the salesperson. On a platform, a cool spray of a foreign brand advertised "the temperature drops by 10.2 degrees Celsius immediately after spraying", and its monthly sales reached 20000 bottles. The consumer, Ms. Lin, told the reporter that the clothes sprayed with spray would feel cold 3 minutes later. However, if spray is accidentally sprayed on the skin surface, the skin will have obvious tingling sensation. It is understood that the cooling spray mainly contains propane, butane, dimethyl ether and other substances with low boiling point. These substances vaporize when heated, and achieve rapid cooling effect by absorbing heat from the clothing surface. Lun Wenhui said that if the cooling spray is sprayed directly on the skin surface, it may cause skin frostbite, or even skin necrosis. In addition, prolonged spraying of the same area should be avoided. In addition, because some cool spray contains essence, it is recommended to spray a small amount of it for testing before use by people with allergies. If there is no allergy or strong skin irritation, it can be used. (Intern reporter Wang Yaoqi, Chai Rong)