Background Anisodamine is widely used in therapy for treating acute glomerulonephritis and diabetic nephropathy because it can improve renal microcirculation.We performed a study to evaluate the preventive effects of anisodamine against contrast-induced nephropathy (CIN) in type 2 diabetics with renal insufficiency undergoing coronary angiography or angioplasty.Methods A total of 260 patients with type 2 diabetes and an estimated glomerular filtration rate (eGFR) of 60 ml-1 ·min-1.1.73 m-2 or less,who were undergoing coronary angiography or angioplasty,were randomly assigned to receive an infusion of either sodium chloride (control group,n=128) or anisodamine (treatment group,n=132).Patients in the treatment group received an infusion of anisodamine at a rate of 0.2 μg · kg-1.min-1 from 12 hours before to 12 hours after coronary angiography or angioplasty,while patients in the control group received an infusion of sodium chloride with the same volume as the treatment group.All patients received intravenous sodium chloride hydration.CIN was defined as a 25％ increase in serum creatinine from baseline or an absolute increase of ＞0.5 mg/dl within three days after contrast exposure.The primary end point was the incidence of CIN.The secondary end point was a 25％ or greater reduction in eGFR.Results There were no significant differences between the two groups with regard to age,gender,risk factors,laboratory results,medications and interventions.The incidence of CIN was 9.8％ (13/132) in the treatment group and 20.3％ (26/128) in the control group (P ＜0.05).The secondary end point was 6.0％ (8/132) in the treatment group and 16.4％ (21/128) in the control group (P＜0.05).Conclusion These results indicate the preventive effects of anisodamine against CIN in type 2 diabetics with renal insufficiency who are undergoing coronary angiography or angioplasty.