Objective To investigate the relationship between the 5-lipoxygenase(5-LO) in mouse lung and during infection in the respiratory system. Methods Investigate the expression of 5-LO in the lung of a mouse by immunocytochemistry. Results The intensity of the immune staining against 5-LO antibody was stronger in infected mice than that in noninfected rats. A weaker immuneoreation was observed in the treated group of animals. Conclusion Changes in the expression of 5-LO in pulmonary tisssues could be designed to detect the treatment efficacy during the lung infection.