本實驗目的在於探討百合萃取粉末於動物體內和體外的抗氧化效應。首先以DPPH自由基清除率(%)來測試百合的體外抗氧化能力。接著採用離乳Wistar 雄鼠進行動物實驗，將32 隻大鼠隨機分為四組：其中包含一個對照組(C組，不含百合粉末)和三個百合實驗劑量組(L為低劑量組，含0.2％百合粉末；M 為中劑量組，含百合粉末1 % ; H 為高劑量組含百合粉末5 %)，每組8 隻，飼養期30 天。 體外試驗結果指出隨著百合濃度增加，對DPPH 自由基清除率有隨之上升之現象。動物經餵食百合粉末飼料30 天後，不管是何種劑量的頁合添加量，皆不影響動物的體重增加與飼料攝取量。血漿中α-生育醇、總抗氧化能力(以Trolox Equivalent表示)和肝臟的還原態麩胱甘肽(GSH)、脂質過氧化指標(T BARS)和α-生育醇含量於四組間皆無顯著差異。肝臟的麩胱甘肽過氧化酶(Glutathione peroxidase, GPx)活性以中劑量組(M組)顯著高於對照組(C組，p ＜0.05)。體外實驗結果指出百合萃取粉末具有清除自由基的能力；動物實驗結果亦指出適當劑量的百合萃取粉末具有提升肝臟抗氧化酵素GPx 活性之能力。 Lily bulb is a traditional medicine and health food in China. The purpose of this study was to examine the antioxidant ability of lily extract in vitro and in vivo. First, the DPPH scavenging effect was conducted to measure the antioxidant ability in vitro. Then, 32 male weaning rats were devideded into four groups according to the following diets : a control diet, or 0.2 % , 1 % , 5 % lily extract-containing diets ( C , L , M , and H, respectively ) . The feeding period was 30 days. The DPPH scavenging effect increased as the concentration of lily extract increased. There were no significant difference in final body weight, feed efficiency and plasma total antioxidant status (Trolox Equivalent ) among the four groups . The levels of thiobarbituric acid-reactive substances ( TBARS ) , reduced glutathione in the liver also showed no significant difference among the four groups . However, the activities of hepatic glutathione peroxidase ( GPx ) were significantly higher in M group when compared with C group ( p < 0.05) . In conclusion ' the lily extract showed free radical scarvenging effect in vitro. The moderate percentage of lily extract in diet could enhance the enzyme activities of GPx in rat liver.