Background: Zhibitai, a natural lipid-lowering Chinese medicine, is well tolerated in patients and has low incidence of adverse events. In this study, we evaluated the efficacy, safety, and side effects of Zhibitai in combination with low dose Atorvastatin compared to high dose Atorvastatin in patients with coronary heart disease or at high risk of coronary heart disease. Methods: This was a randomized, double-blind, multi-center clinical trial on 720 patients with coronary heart disease or at high risk of coronary heart disease. The patients were randomly assigned to a Zhibitai-Atorvastatin group (480 mg Zhibitai twice daily plus 10 mg atorvastatin once daily) or Monotherapy group (40 mg Atorvastatin once daily). Blood samples were obtained at baseline, week 4, and week 8 after a minimum 8-hour fast. Efficacy was evaluated in terms of the changes in the following parameters: lipoprotein profiles [total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C)]. Safety was assessed throughout the study by clinical laboratory tests including liver function [alanine transaminase, aspartate transaminase] and renal function [blood urea nitrogen], and creatine kinase; physical examination; and adverse events monitoring. Results: TC, TG, LDL-C levels were significantly decreased andHDL-C levels were significantly increased at week 4 and week 8 (all P < 0.05) in both groups but had no significant differences between the two groups (P > 0.05). In subgroup analyses, Zhibitai-Atorvastatin Group produced significantly greater reduction in TG compared with Monotherapy Group at week 8 in patients with TG > 203.72mg/dL (P < 0.01). Among patients with LDL-C levels > 131.48 mg/dL, Zhibitai-Atorvastatin Group produced a greater reduction of LDL-C levels compared with the Monotherapy Group at week 4 (P < 0.05). The incidence of liver dysfunction, headache, or gastrointestinal intolerance was significantly lower in the Zhibitai-Atorvastatin Group compared with Monotherapy Group during the 8-week study peroid (P < 0.001). There were no significant differences in renal function, myopathy, and other adverse events between the groups. Conclusion: Overall the two groups have similar lipid regulation efficacy. Zhibitai plus low dose Atorvastatin is more efficacious in lowering TG in patients with TG > 203.72 mg/ dL at week 8. There are fewer side effects in Zhibitai plus low dose Atorvastatin group. Long term follow up is required to evaluate cardiovascular outcomes. © Xu et al.