Lemongrass (Cymbopogon citratus  DC, Stapf.), a member of family Poaceae, is commonly used to cure several diseases. Lemongrass aqueous extract (LGE) and LGE-loaded chitosan nanoparticles (LGE-CSNPs) exhibited potential effectiveness as antioxidant, anti-diabetic, and protective effects in male rats. Reducing power, free radical scavengers and Haemolytic activity of LGE and LGE-CSNPs were evaluated on protein levels. Total phenolics and total flavonoid contents were studied using (HPLC). Six groups of thirty-six adult male albino rats were given three different measurements of C. citratus LGE-CSNPs orally.  Antioxidant activities and oxidative stress of LGE-CSNPs were evaluated on protein levels. Diabetic parameter (HBA1C) was determined. Pancreatic histopathological examinations were also studied. The sensory properties of this blind as a food supplement to fermented milk (Rayeb milk) were also evaluated.  The polyphenol fingerprint of LGE revealed that chlorogenic acid (14.56 mg/ml), and quercetin (18.25 mg/ml) were the major polyphenols present in this extract. Glutathione peroxidase (GPx) of LGE-CSNPs as antioxidant activity was more active than LGE. Thiobarbituric Acid Reactive Substance (TABRAS) as oxidant concentrations and free radical scavengers have been decreased in the reference drug (Metformin), LGE, and LGE-CSNPs-treated rat groups compared to the control group (untreated). LGE-CSNPs (5 mg/kg Bwt) exhibited the lowest levels of TABRAS and (GPx). Diabetes parameters have been decreased in LGE-CSNPs (5 mg/kg Bwt) (5.13) in comparison with the reference drug (5.62). Results suggested a natural nutritional supplement that improves diabetics' condition of health. It is recommended to be added to fermented milk (Rayeb milk) as a nutritional supplement.