ObjectiveTo observe the effect of irbesartan and triptolide combination on the level of urine protein in patients with diabetic nephropathy at high altitude area.MethodsFifty patients with diabetic nephropathy (24-hour urine protein excretion over 1.0 g and serum creatinine level below 265.2 μmol/L) at high altitude area were randomly divided into two groups,the control group were treated with irbesartan 150 mg/d for three months,and the treatment group received irbesartan 150 mg/d combined with triptolide 40 mg/d for three months.24-hour urine protein concentration,arterial pressure,liver function and renal function were measured before and after the treatment.Results After three months' treatment,the levels of 24-hour urine protein and arterial pressure were significantly lower in both control and treatment group (P ＜ 0.01 ).Twenty-four hour urine protein in treatment group were reduced from ( 8.34 ± 1.29) g before treatment to (6.42 ± 0.95 ) g after treatment ( t =5.994,P ＜ 0.001 ).Twenty four-hour urine protein in control group were reduced from (8.57 ± 0.53 )g before treatment to (7.10 ± 0.79 )g after treatment( t =7.730,P ＜ 0.001 ).Systolic pressure in treatment group were reduced from ( 152.04 ± 18.80)mm Hg before treatment to ( 131.24 ± 10.56)mm Hg after treatment(t =4.817,P ＜ 0.001 ) ; Diastolic pressure in treatment group was reduced from (93.60 ± 11.36 )mm Hg before treatment to ( 82.68 ± 7.30) mm Hg after treatment ( t =4.053,P ＜ 0.001 ).Systolic pressure in control group were reduced from ( 151.20 ± 10.17 ) mm Hg before treatment to ( 130.00 ± 10.10 ) mm Hg after treatment(t =7.396,P ＜ 0.001 );Diastolic pressure in treatment group were reduced from (92.76 ± 7.03 )mm Hg before treatment to (84.20 ± 7.56)mmHg after treatment (t =4.147,P ＜ 0.01 ).No statistic differences were observed in liver function and renal function before and after the treatment ( P ＞ 0.01 ).Conclusion Irbesartan and triptolide combination can reduce 24-hour urine protein to a certain extent and donot adversely affect liver function and renal function in patients with diabetic nephropathy at high altitude area