There are several factors that make a cold long: First, because the body’s immunity is too low, the body’s immune response is poor or the body’s endocrine disorders, immune dysfunction, it will produce a lack of immune defense function, can not effectively remove the cold virus, bacteria or pathogenic microorganisms, produce symptoms, will delay the cold time, so that a long time not to heal. Second, the long duration of the cold is also due to the incorrect choice of medication and method, when the cold needs to identify whether it is a wind-heat type of cold or a wind-cold type of cold, such as contradiction in the use of medication, the use of medication on the contrary, which will lead to the effect of the drug is not ideal, and even affect and delay the condition. Third, when the cold combined with other symptoms, such as tuberculosis, tumors, anemia, immune and connective tissue diseases, blood system diseases, tumors and other factors, will prolong the time of the cold does not heal.