本研究目的主要探討台灣栽培的黃花石斛及有瓜石斛市售品的抗氧化活性及對四氯化碳誘導的急性肝臟傷害的保護效果，以總多酚和類黃酮含量試驗來評估四種石斛活性成分含量，再以 DPPH 自由基清除試驗和還原力試驗以及亞鐵螯合能力試驗等三種抗氧化能力試驗來評估二種石斛的抗氧化活性，再探討其對四氯化碳誘導的急性肝損傷的保護效果，測定 catalase, SOD,GPX, GSH, GR, GST 及 MDA，最後觀察其肝臟病理切片以探討石斛保護四氯化碳誘導急性肝損傷之機轉。實驗結果顯示，有瓜石斛及黃花石斛均含有多酚及類黃酮，在體外抗氧化實驗中，具有抗氧化效果。有瓜石斛及黃花石斛對四氯化碳所引起血清AST 及 ALT 活性升高有顯著降低，並減少 MDA 濃度，此結果與病理切片結果一致。有瓜石斛及黃花石斛可以提升因四氯化碳所減少抗氧化酵素活性和GSH 濃度。綜合實驗結果，顯示有瓜石斛及黃花石斛具有抗氧化活性及保護四氯化碳誘導的急性肝臟損傷，其保護機制可能經由提升自由基清除酵素的活性及GSH濃度來達到保護效果。This study was intended to investigate the anti-oxidative activity, anti-oxidative substance content and the protective effect of Dendrobium tosaense (DT) and Ephemerantha fimbriata (EF) on carbon tetrachloride-induced acute liver injury. Firstly, we detected the contents of total polyphenols and flavonoids in the DTEtOH and EFEtOH. Second, the anti-oxidative activities of the DTEtOH and EFEtOH were determined using DPPH free radical scavenging assay, reducing power assay, ferrous metal-chelating capacities assay in vitro. Finally, the hepatoprotective effect of DTEtOH and EFEtOH was determined using CCl4-induced acute liver injury. The activities of serum alanine aminotransferase (sALT), serum aspartate aminotransferase (sAST), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), the levels of glutathione (GSH) and malondialdehyde (MDA) were measured. The results were confirmed by liver histology. DTEtOH and EFEtOH possessed anti-oxidative activity and polyphenol content. When mice were treated with CCl4 in the absence of DTEtOH and EFEtOH, the activities of sALT and sAST, and MDA level were increased, while the activities of antioxidant enzymes (SOD, GPx, catalase, GR, GST) and GSH level were decreased. When the mice were treated with CCl4 in the presence of DTEtOH and EFEtOH, the activities of sALT and sAST, and MDA level were significantly decreased, while the activities of antioxidant enzymes, and the GSH level were increased. The above results were confirmed by liver histological examination. DTEtOH and EFEtOH possessed anti-oxidative activity and protected against CCl4-induced acute liver injury in mice by increasing the anti-oxidant enzymes activities and GSH level.