The common reasons why pneumonia infusion is useless are: first, the selection of antibiotics does not cover the causative bacteria. In this case, bacteriological examination, culture and drug sensitivity tests need to be improved, and sensitive antibiotics should be selected according to the results of drug sensitivity tests. Second, the drug dose is not enough, the drug dose needs to be adjusted so that the patient can achieve an effective blood concentration. Third, pneumonia may be combined with other diseases. Clinically, there are often other diseases combined with pneumonia, such as obstructive inflammation due to lung cancer, tuberculosis, pulmonary isolation, etc. Patients cannot recover from the disease with only anti-infective treatment. So pneumonia treatment with drug infusion is ineffective, need to clarify the cause of the disease, according to the cause of specific treatment.