Diabetes mellitus is a chronic metabolic disorder characterized by increased blood glucose levels due to decreased insulin production, insulin action or both. Red guava fruitghurt contains flavonoid phytochemical compound. This research aims to determine the effect of red guava fruitghurt on reducing blood glucose levels in rats. The study was laboratory experiment. The subjects of this study were white rats (Rattus norvegicus) with wistar lines, where each group needed 5 rats, therefore the total was 25 rats. The sampling technique used is simple random sampling, The experimental animals are grouped into 5 groups, negative control, positive control, treatment 1 (administration of fruitghurt), treatment 2 (administration of glibenclamide), and treatment 3 (combination of fruitghurt and glibenclamide). The data analysis was performed with paired t test, one way anova, pairwise comparison test and post hoc duncan. The study found that red guava fruitghurt can reduce blood glucose levels in rats induced by streptozotocin and show a probability value or p value of 0.000 (p value < 0.05), meaning that there is a significant difference between Treatment 1, 2, and 3. The blood glucose level of rats after administration of fruitghurt was 75.4mg/dl, after administration of glibenclamide was 48.4mg/dl and the combination of fruitghurt and glibenclamide was 44.0mg/dl. From these data, it can be seen that the most influential treatment in reducing blood glucose levels is the combination of fruitghurt and glibenclamide. The significant effect in lowering blood glucose levels is the combination of fruitghurt and glibenclamide. DOI : 10.35990/amhs.v1n1.p19-27 REFERENCES Khairani, R. (2016). Prevalensi diabetes mellitus dan hubungannya dengan kualitas hidup lanjut usia di masyarakat. Universa Med, 26(1). Newman, W. A., & Kamus Saku Kedokteran Dorland. (2011). Kamus Saku Kedokteran Dorland (Ed. 28, Vol. 28). 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