Cold once a month belongs to a non-normal situation, normal adults should have a cold once a year or once a quarter, if a cold once a month is the following factors: 1, colds do not heal because of the body’s immunity and resistance is too low, there are vitamins, micronutrient deficiencies will result in immunity and resistance is too low. 2, primary systemic diseases caused by organ function decline and regression, such as chronic Obstructive lung disease can cause chronic emphysema, which can cause the immunity of the respiratory system to decline and low barrier function.3, coronary heart disease, stroke, cerebrovascular disease sequelae can also lead to the body’s immune dysfunction, so there is the occurrence of a cold once a month.4, rare connective tissue diseases, such as rheumatism, rheumatoid arthritis, or tuberculosis, systemic lupus erythematosus, or even severe anemia, Tumors, AIDS, etc. will occur once a month due to immune disorders.