AIM: To observe the effect of fudosteine on induced sputum cell components and lung function in patients with stable neutrophil-dominated COPD. METHODS: From October 2019 to October 2022, 53 patients with stable COPD were selected and divided into fudosteine group and placebo group. The placebo group was treated with routine treatment, and the fudosteine group was treated with fudosteine on the basis of routine treatment. The two groups were treated for 6 months. The clinical symptoms ［Saint George's Respiratory Questionnaire (SGRQ), COPD Assessment Test (CAT) and Modified British Medical Research Council Dyspnea scale (MMRC), Breathlessness, Cough, and Sputum Scale (BCSS)］, lung function index, induced sputum cytology analysis and other related examination results were recorded in detail before and after treatment. RESULTS: (1) Compared with the baseline, the forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and the ratio of FEV1 to FVC (FEV1/FVC) of the two groups were improved after treatment, and the differences were statistically significant (P<0.05). However, after treatment, there was no significant difference in pulmonary function between the two groups except for the percentage of carbon monoxide diffusion in the predicted value (DLCO%pre) (DLCO%pre in the fudosteine group was higher than that in the placebo group). (2) After treatment, the total number of induced sputum cells and neutrophil counts in the fudosteine group were lower than those in the placebo group. Compared with the number of cells in each component at baseline, the total number of induced sputum cells and neutrophil count in the fudosteine group were significantly lower (P<0.05). CONCLUSION: Fudosteine treatment in patients with stable neutrophil-dominated COPD can improve lung function, reduce the total number of induced sputum cells and the total number of neutrophils, thereby improving airway inflammation.