Diabetes mellitus is a chronic disease characterized by hyperglycemia or blood glucose levels exceeding normal values. Non- pharmacological treatment of diabetes mellitus can use herbal plants, such as mangosteen peel. Research Objectives:The purpose of this study was to determine the effect of mangosteen peel on reducing blood sugar levels in patients with diabetes mellitus at the Rawang Panca Arga Health Center. Methods:This type of research uses quasy experimental method with one group pretest posttest design. The population in this study were all patients with diabetes mellitus as many as 40 people. The number of samples taken in this study were 40 patients with diabetes mellitus with total sampling technique. Data analysis using the Wilcoxon test. Results:of the study Blood sugar levels in patients with diabetes mellitus before being given mangosteen skin (pretest) all had KGD ≥180 mg/dL with uncontrolled blood sugar levels as much as 100%. Blood sugar levels in patients with diabetes mellitus after being given mangosteen skin regularly decreased KGD < 180 mg/dl with controlled blood sugar levels by 70% or 28 people. The results of the statistical test analysis obtained a p value = 0.000 (p <0.05), this means that there is a significant effect of mangosteen skin administration on reducing blood sugar levels in patients with diabetes mellitus at the Rawang Panca Arga Health Center. Conclusion: These results prove that the administration of mangosteen peels is effective in reducing blood sugar levels <180 mg/dL with controlled sugar levels in patients with diabetes mellitus at the Rawang Panca Arga Health Center. It is hoped that health workers can provide counseling on the use of mangosteen skin in helping to reduce blood sugar levels in people with DM.