Traditional Chinese medicine (TCM) has recorded knowledge of diabetes for over 2000 years. Because a considerable number of TCM studies exhibit design defects, such as limited intervention duration, small sample sizes, and inconsistent efficacy evaluations, the role of TCM in the treatment of diabetes cannot be fully elucidated. In this review, we evaluated randomized controlled trials (RCTs) of prediabetes, diabetes, and diabetic complications published in the past decade. We found that TCM could significantly improve glucose control and clinical indices in patients with diabetes and effectively delay the progression of diabetes. We also summarized potential pharmacological mechanisms underlying the efficacy of TCM medication/herb and their active ingredients for treating diabetes mellitus (DM). More rigorously-designed experiments and long-term evaluation of TCM for diabetes will allow for more effective diabetes management. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.