進行10-250 mg/kg Rauwolfia serpentina 根甲醇萃取物（MREt）的急性毒性研究，以不同群組血糖正常Wister 小鼠（6/組）實驗，觀察降血糖活性和行為模式，包括鎮靜作用和死亡率。給小鼠口服10-60 mg/kg MREt ，30分鐘後無鎮靜效果，但有降血糖作用，血糖平均值從80降到62 mg/dL，若將MREt劑量增加為100-250 mg/kg ，則有鎮靜作用，且4 小時內的死亡率從17增到100%。依據劑量和死亡率的迴歸線圖，MREt的LD50 平均值為141.25 mg/kg（log LD50 = 2.15 mg/kg）。相對於控制組和陰性控制組（給予0.05% dimethylsulfoxide @ 1 mg/kg），口服葡萄糖耐受試驗中MREt劑量為10、30和60 mg/kg 時，降血糖活性顯著，0 、30和60分鐘血糖下降範圍
分別為31-65，39-49 及25-51%。雖然100 mg/kg MREt從0 到120 分鐘都具降血糖活性，卻會誘發輕微鎮靜作用和實驗小鼠的死亡。結果顯示，10-60mg/kg MREt於小鼠不發生鎮靜作用並能有效地降低小鼠血糖，但大於100mg/kg 的劑量則有致死效果，表現於鎮靜作用和死亡率。因此，小劑量的
MREt可以在胰臟或胰外之階段增強葡萄糖耐受量。

In the present study, acute toxicity of methanolic root extract (MREt) of Rauwolfia serpentina (10 - 250 mg/kg) was observed in terms of hypoglycemic activity and behavior pattern including sedation and mortality rate in different groups of normoglycemic wister mice (6/group). Orally administrated MREt (10 to 60 mg/kg) was found non-sedative and showed hypoglycemic activity by reducing the mean blood glucose level from 80 to 62 mg/dL after 30 min of administration while the doses (100-250 mg/kg) of same extract showed sedation and mortality rate from 17 to 100% within 4 h. The value of median lethal dose (LD50) of MREt of R. serpentina was 141.25 mg/kg (log LD50 = 2.15 mg/kg) from graph plotted between log-doses verses probits. In oral glucose tolerance test, MREt (10, 30 and 60 mg/kg) showed significant hypoglycemic activity at 0, 30 and 60 min by deceasing blood glucose level ranging from 31- 65%, 39 - 49% and 25 - 51% respectively compared to control and negative control (treated with 0.05% dimethylsulfoxide @ 1 mL/kg) groups. However, MREt (100 mg/kg), though hypoglycemic from 0 to 120 min, induced slight sedation and mortality in experimental mice. The results indicated that the MREt (10 - 60 mg/kg) was non-sedative and effective in lowering the blood glucose level in mice but showed lethal effect in terms of sedation and mortality at doses ≥ 100 mg/kg. Therefore, MREt of R. serpentina in small doses can improve the glucose tolerance either at pancreatic or extra-pancreatic level.