As long as the toothbrush is used for a period of time, there will be a large number of bacterial growth and reproduction, including Candida albicans, hemolytic streptococcus, pneumococcus and so on. These bacteria will directly invade the human digestive tract and the inhalation tract through the oral cavity, which may cause enteritis and lung infections, etc. At the same time, if it enters the human bloodstream through the oral mucous membrane breakage, it will cause serious blood diseases. So in general after the use of toothbrushes, in addition to should try to keep the toothbrush dry, it is best to often put the toothbrush in the sun exposure sterilization, usually put the toothbrush toothpaste should be the best place is ventilated and dry, otherwise it will breed bacteria and other harmful microorganisms. The frequency of toothbrush renewal should be between one month and two months.