Objective To investigate the influence of indomethacin to the unite treatment effect on chronic phase myeloid leukemia (CML-CP) with interferon alpha-2b (IFNα-2b) and low dose cytarabine (LD-Ara-C).Methods 22 CML-CP patients were randomly divided into two groups.Control groups (10 cases) injected with IFNα-2b (3 million units),injection frequency was q.o.d,the duration of treatment was about 3-18 months,cytarabine (Ara-C) by slowly intravenous driped (30 mg/d).In this treatment schedule,every course of treatment sustained 10 days,and with a 2 weeks interval.During this process,patients in treatment group were treated with hydroxyl urea only when their WBC in peripheral blood exceed 20×109/L,otherwise,discontinue it.Treatment group (12 cases),on the first day of treatment with IFNα-2b and Ara-C,added indomethacin (25 mg) through oral administration,the frequency was t.i.d.During treatment in the two group,the end point of observation was completely hematology ease,at the same time,these indicators in the two groups needed to be compared,the time when WBC begin to fall,the time when WBC fall to normal range,the time when immature cells returned to normal,the time which complete hematological remission and the highest temperature of patients after IFNα-2b was subcutaneous injected.Results The time when WBC begin to fall in treatment group was (4.2±2.7) d,and the time was (5.0±2.5) d in control group (t =0.714,P ＞ 0.05).In treatment group,the time when WBC fall to normal range was(10.0±4.5) d,and the time was (12.0±4.5) d in control group (t =1.036,P ＞ 0.05).The time when immature cells returned to normal in treatment group was (14.2±4.8) d,and the time was (19.0±3.6) d in control group (t =2.609,P ＜ 0.02).The time which complete hematological remission was achieved in control group was (45.8±5.6) d,but it was (53.9±10.5) d in control group (t =2.314,· P ＜ 0.05).Meanwhile,the fever degree after IFNα-2b was subcutaneous injected obviously achieved improvement in treatment group (x2 =12.041,P ＜ 0.005).Conclusion The advantage of indomethacin to the unite treatment with IFNα-2b and LD-Ara-C on CML mainly lays in which cound alleviated the adverse reaction such as flu-like of IFN,and more,there are synergy effect in antagonist CML.