In our study was investigated the in vitro effects of Colistin(4 mu g/ml), alone with the combination of tigecycline(0.87 mu g/ml), imipenem (30 mu g/ml) and rifampicin (7 mu g/ml) at therapeutic concentrations and malondialdehyde (MDA) level, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and myeloperoxidase (MPO) activity on polymorphonuclear leukocyte (PMN) functions (phagocytic and intracellular killing activity) of patients with bronchiectasis. PMNLs were isolated from venous blood by Ficoll-hypaque gradient centrifugation method. Phagocytic activity and intracellular killing activity were assayed by modified Alexander's method. MDA levels were determinated by Beuge's method, SOD, GSH-Px and MPO activities were assayed by Sun's, Paglia and Valentine's and Hillegas's, methods respectively. All results are statistically evaluated. Phagocytic (p<0.0001), and intracellular killing activity (p=0.0113, p=0.0008, p=0.0014, p=0.0036) in the PMN of patients with bronchiectasis significantly increased when compared to the control. Enzyme activity (SOD, GSH-Px and MPO) and MDA level significantly decreased (p<0.001) in patients with bronchiectasis when compared to the control.