Pneumonia is a severe infection that causes high morbidity and mortality rate worldwide. It is caused by Klebsiella pneumoniae, which generally causes upper respiratory tract infection. In case of such type of infection, levels of oxidant and antioxidant become imbalanced, which may contribute to lung injury. The present study was planned to evaluate the status of oxidant and antioxidant enzyme activities in plasma and lung tissue of pneumonia-infected rats model. Animals were randomly distributed into 3 groups of 8 rats each: groups I (control, normal saline treated), II (infected group), and III (infected + treated group). The findings showed that there was significant increase (P < .001) in body temperature along with decreased body weight in the infected group as compared to the control group. Similarly, all the activities of antioxidant enzymes (superoxide dismutase [SOD], catalase) were significantly decreased along with increased malonaldialdehyde (MDA) levels in plasma and lung tissue of the infected group as compared to the control group. These enzyme activities along with MDA levels were improved and came back near to normal level after administration of cefepime plus amikacin (potentox) for 7 days in group III. These studies concluded that fixed-dose combination of potentox improved oxidant and antioxidant levels in pneumonia infection.