This study is a randomized prospective double-blind, accomplished with sealed envelopes ,with two groups :
* Group A: Short treatment duration: 1 tablet Levofloxacin 500mg / day for two days completed by 1 tablet Placebo Levofloxacin 500mg / day for the remaining 5 days.
* Group B: Standard treatment duration (control group): 1 tablet Levofloxacin 500mg / day for 7 days.
The study is conducted by recruiting AECOPD patients to collect their blood samples and sputum samples. These samples will be used for the inflammatory analyses and the study of bacterial and viral serology. The results were seized by the SPSS.20.0 software.
