Colds after chemotherapy are usually caused by the decrease of body resistance. Because chemotherapeutic drugs are through a wide range of cellular effects, not only on the tumor cells to play a role in killing, on the normal body tissue cells also have a killing effect. Therefore, chemotherapy will cause some damage to the body’s immune system, thus causing the patient’s immunity to be low, and thus prone to colds. For chemotherapy personnel must pay attention to protection, especially the high risk of influenza season, after chemotherapy must avoid contact with people with colds. At the same time wear masks, especially wear protective masks, such as N95 and other masks, ordinary masks generally have no defense against viral colds. At the same time to enhance the nutrition, you can also take oseltamivir and other anti-flu drugs for flu prevention, the prevention of colds has a very positive effect.