According to the principle that heat must be treated with cold prescription, heat-clearing prescription mainly consists of cold medicine with the function of clearing heat, purging fire, cooling blood, engendering saliva and detoxification. It is used to treat interior heat syndrome, which includes the heat of Qi and blood, excess-heat and deficiency-heat syndrome, abnormal exuberance of different organs, damp-heat and summer heat syndrome. Thus clearing agent prescription can be divided into heat-clearing fire-purging prescription, heat-clearing detoxificating prescription, prescription for clearing nutrient level and cooling blood, prescription for clearing organs heat, heat solution prescription, prescription for clearing deficiency-heat.