There is no best injection for the treatment of pneumonia, because when choosing drugs, it is necessary to combine the pathogenic bacteria as well as physical condition, age factors and so on to do a comprehensive consideration. For example, the common cause of pneumonia Streptococcus pneumoniae, in general, you can choose penicillin, ceftriaxone, cefotaxime sodium, amoxicillin, and fluoroquinolones, but fluoroquinolones can not be applied to people under eighteen years of age. In case of drug-resistant bacteria, vancomycin and linezolid can be used, but vancomycin cannot be used in patients with poor renal function. Another example is the treatment of mycoplasma pneumonia, you can choose doxycycline, macrolides, such as azithromycin and fluoroquinolones, that is, levofloxacin and ofloxacin. But these three drugs in the fluoroquinolones on the adult effect is better, but under eighteen years of age can not be applied to the crowd, only to choose macrolides, its is a very good drug. Doxycycline has a certain effect on the bone marrow, and generally not as the first choice. So the choice of which class of injection is the best, it is necessary to combine many factors to consider, in order to make a decision, choice.