When you have a cold and cough, you can drink a little China Green Tea, because green tea is very rich in vitamin C, which can enhance the immune activity of cells and has a certain effect on resisting pathogens. Green tea also contains a certain amount of caffeine, which has a certain effect of promoting cough relieving. Moreover, green tea contains a certain amount of theophylline, which can expand and dredge the airway to a certain extent. Therefore, drinking some green tea when you have a cold or cough can relieve the cough, which is beneficial to the condition.