Moringa oleifera grown and used in many countries around the world is a multi-purpose tree with medicinal and nutritional values. This study evaluates the effect of taking moringa oleifera leaves powder on blood sugar levels in humans, and study side effect on kidney (urea, creatinine) and liver enzyme (AST, ALT) after taken leaves powder for a month. The study targeted patients who their blood glucose not lowering by drugs. Blood glucose, urea, creatinine, AST and ALT for all diabetic patients was determined before and after taking 0.5g leaves powder. Results showed blood sugar levels decreased statistically significant (p<0.001) for all diabetic patients, and no statistically significant difference in the mean values of urea, creatinine, (AST) and (ALT) before and after taking leaves powder (p˃0.001). This study concluded that leaves powder have a significant impact on anti-diabetic property for the selected patients, so it's promising in the prevention for risk of diabetes mellitus.