Every time there is a cough, the final diagnosis is due to mycoplasma infection. This situation is mainly due to the patient’s resistance is relatively poor, weak, and the patient in the treatment of Mycoplasma pneumoniae infection is not standardized, not completely cured. And under normal circumstances, the body’s respiratory tract, such as the mucous membrane of the nasopharynx, will be attached to the parasitic normal flora mycoplasma, which will not increase in the case of normal human immunity. Patients in the exertion, fatigue, rain, cold, alcoholism and other triggers to make the immune system decline, will lead to airway mucosa of the immune barrier is damaged, so that the mycoplasma will gradually multiply and increase, invade into the airway to form pathogenic bacteria, so easy to relapse.