Type 2 diabetes mellitus (T2DM) and impaired glucose tolerance (IGT) are growing public health challenges. Early intervention in mild T2DM and IGT is essential to prevent disease progression and severe complications. Traditional Chinese Medicine (TCM) provides a potential therapeutic approach. Sanggua tablets, a TCM formula composed of mulberry leaf, bitter melon, kudzu root, Chinese yam, and cassia seed, embody TCM principles of clearing heat, generating body fluids, tonifying the spleen and stomach, and nourishing the lungs and kidneys. Modern studies show that Sanggua tablets effectively lower blood glucose and improve lipid profiles through components like mulberry polysaccharides and bitter melon saponins. These findings suggest their potential as an alternative or complementary therapy for mild T2DM and IGT. This study will conduct a randomized, double-blind, placebo-controlled, parallel-group clinical trial among patients with IGT and mild T2DM. Participants will receive a 16-week intervention with Sanggua tablets. The primary outcome is glycated hemoglobin (HbA1c), with secondary outcomes such as fasting blood glucose (FBG), fasting insulin (FINS), HOMA-IR, lipid profiles and so on. Safety will be closely monitored. Additionally, fecal samples will be collected for 16S rDNA sequencing to explore the role of gut microbiota in the therapeutic effects of Sanggua tablets. This study aims to provide evidence for the clinical application and development of Sanggua tablets as a novel TCM therapy.