Abstract Background Real-world evidence on the effectiveness and safety of herbal medicines for type 2 diabetes mellitus (T2DM) remains limited despite promising results from controlled studies. This study aimed to evaluate the clinical outcomes of Hyeoldanggaesun-tang, a traditional Korean herbal formulation, in routine clinical practice. Methods This multicenter retrospective chart review included 31 adults with T2DM who received Hyeoldanggaesun-tang continuously for 6 months across four Korean medicine clinics. Clinical and laboratory data were extracted at baseline and at 3 and 6 months. The primary outcome was change in glycated hemoglobin (HbA1c). The secondary outcomes included liver enzymes, lipid profiles, blood pressure, body mass index, and safety indicators. Results Mean HbA1c decreased significantly from 8.85 ± 2.01% at baseline to 7.51 ± 1.32% at 3 months and 7.01 ± 1.18% at 6 months (both p < 0.001), corresponding to a large effect size (Cohen’s d = 1.01 at 6 months). Significant improvements were also observed in liver function markers, including alanine aminotransferase (45.82 ± 17.05 to 40.34 ± 18.32 U/L), aspartate aminotransferase, and gamma-glutamyl transferase (all p < 0.01). Triglyceride levels decreased from 170.25 ± 137.49 to 144.33 ± 110.07 mg/dL ( p < 0.001), while high-density lipoprotein increased and low-density lipoprotein decreased significantly over time. No significant changes were observed in body mass index or renal function. Three patients reported mild adverse events, none of which required treatment discontinuation. Notably, 14 patients reduced or discontinued conventional antidiabetic medications during follow-up while maintaining improved glycemic control. Conclusion Hyeoldanggaesun-tang was associated with clinically meaningful improvements in glycemic control, liver enzymes, and lipid profiles, with a favorable safety profile. These findings support its potential role as a complementary therapy for T2DM and warrant confirmation in prospective randomized controlled trials. Graphical Abstract
Son et al. (2026) studied this question.