These studies were conducted to investigate effects of Prunus mume extract on experimentally alloxan-induced diabetes in rabbites, antibacterial activity and acute toxicity in mice ; 1. $LD_{50}$ of Prunus mume extract(P.M.E.) was 15.25g/kg intraperitoneally in mice. 2. P.M.E. showed more significant recuperative effect compared to the control group in alloxan-induced diabetes of rabbits. 1) P.M.E. 800mg/kg bodyweight exhibited more excellent hypoglycemic effect afte 6 days and adjacent to the normal level at 14th day. 2) SGPT activity was significantly decreased after 6 days, and the blood levels of total cholesterol and urea-nitrogen were significant in 800mg/kg at 6 days and 10 days respectively. 3. In antibacterial activity test P.M.E. was active at 0.195mg/kg in Staphyllococcus aureus, 3.125mg/ml in E. coli, Enterobacter cloacae, Klebsiella oxytoca, and in Pseudomonas aeruginosa at 0.391mg/ml. 4. In histological findings, the sample groups were deeply stained, fully granulated and partial degranulation of ${eta}-cells$, and a few vacuolar and vesicular changes of cytoplasm than alloxan treated group in proportion to the sample amounts.