Context: Berberine, a natural plant alkaloid, is usually used as an antibiotic drug. The potential glucose-lowering effect of berberine was noted when it was used for diarrhea in diabetic patients. In vitro and in vivo studies have then showed its effects on hyperglycemia and dyslipidemia.

Objective: To evaluate the efficacy and safety of berberine in the treatment of type 2 diabetic patients with dyslipidemia.

Design: 116 patients with type 2 diabetes and dyslipidemia were randomly allocated to receive berberine(1.0g daily) and the placebo for 3 months. The primary outcomes were changes in plasma glucose and serum lipid concentrations. Glucose disposal rate (GDR) was measured using a hyperinsulinemic euglycemic clamp to assess insulin sensitivity.

Results: In berberine group fasting and post load plasma glucose decreased from 7.0±0.8 to 5.6±0.9 and from 12.0±2.7 to 8.9±2.8 mM/L, HbA1c from 7.5±1.0% to 6.6±0.7%, triglyceride from 2.51±2.04 to 1.61±1.10 mM/L, total cholesterol from 5.31±0.98 to 4.35±0.96 mM/L, and LDL-cholesterol from 3.23±0.81 to 2.55±0.77 mM/L, with all parameters differing from placebo significantly (p<0.0001, p<0.0001, p<0.0001, p=0.001, p<0.0001, and p<0.0001, respectively). The GDR was increased after berberine treatment (p=0.037), although no significant change was found between berberine and placebo groups (p=0.063). Mild to moderate constipation was observed in 5 participants in berberine group.

Conclusions: Berberine is effective and safe in the treatment of type 2 diabetes and dyslipidemia.