Dirty bed sheets are the “home base” of germs. The human body sheds millions of skin cells every day, most of which are shed while sleeping and accumulated on the bed sheets. In addition, the body will also secrete body fluids, sweat and oil, these metabolic wastes will become a breeding ground for dust mites, bacteria. If people inhale or come into contact with these dust mites, bacteria or their metabolic wastes, they are likely to cause allergies, asthma and rhinitis, and in severe cases, eczema. Dust mite, a small eight-legged monster that cannot be seen with the naked eye, is about 0.02 mm long and is the most common mite in the living room. It uses human sweat, secretions, and shed dander as a source of nutrition, and likes warm, humid, and dark environments (20-30 degrees Celsius, 50%-70% humidity) most, similar to human living environments. Dust mites have an amazing ability to reproduce, with females laying 25-50 eggs at a time, with a reproduction cycle of every three weeks. Once dust mites are present in a room, it is very difficult to remove them completely. About 90% of children with asthma are allergic to house dust mites, and about 80% of patients with allergic asthma, allergic rhinitis, and dermatitis are related to dust mites. Dust mites trigger allergies mainly because their secretions, excretions and decomposing bodies contain more than 15 different forms of harmful proteins, often only about 10 microns in diameter, which can be inhaled deep into the human lungs and become allergens, causing allergic diseases in humans. In addition to inducing asthma, dust mites also cause allergic rhinitis, allergic conjunctivitis and allergic skin diseases. Allergic conjunctivitis is mainly manifested by itchy eyes, tearing, red eyes and congested and edematous lid conjunctiva, while allergic rhinitis is mainly manifested by runny nose and sneezing. People should change their bed sheets at least once every two weeks. When changing bedspreads and sheets, you may want to use a vacuum cleaner or a slightly damp rag in passing to clean up the dander and hair left on the mattress. If there are stains, soap can be used to apply dirty, and then dry with a dry cloth, so as not to gradually mold, odor. After changing the sheets, it is best to open the window to pass a while wind, to prevent the replacement process, due to shaking and diffusion of small particles in the air, stimulating the respiratory tract, causing discomfort. Change down the sheets to be soaked in hot water with more than 60 ℃ washing 15-20 minutes, after washing to be dried or dried in time to achieve the effect of sterilization. In order to play the best antibacterial effect, you can also use the cheapest germicidal agent – bleach, but the use of the best concentration is lower. If the hand-washing method, you can add the right amount of hydrogen peroxide in cold water, can also play a sterilizing effect. During the day, it is best to cover the sheets and pillows with a dense bedspread, which can prevent bacteria and dust.