用倒置显微镜、光镜、电镜的形态学方法和ＤＮＡ断片检测方法观察了人食管癌Ｅｃａ－１０９细胞在５—Ｆｕ作用后的形态学变化和生化改变。结果，肿瘤细胞回缩变圆，体积缩小，有的细胞呈出芽状。核染色质凝聚、环状核形成、核碎裂及凋亡小体形成。在５—Ｆｕ浓度较低时（１—１０μｇ／ｍｌ），凋亡的细胞较少见；当增加药物浓度达３０μｇ／ｍｌ以上时，尤其在４８ｈ以后，细胞凋亡很明显。结果提示，５—Ｆｕ可以诱导Ｅｃａ－１０９细胞凋亡。 The morphology and biochemical changes of human esophageal cancer Eca-109 cells after 5-Fu treatment were observed by morphological methods of inverted microscope, light microscope and electron microscope and DNA fragmentation detection. As a result, the tumor cells retracted and round, and the volume was reduced. Some cells showed buds. Nuclear chromatin condensation, ring nucleus formation, nuclear fragmentation and formation of apoptotic bodies. At low concentrations of 5-Fu (1-10 μg/ml), apoptotic cells were less common; when the concentration of the drug increased above 30 μg/ml, especially after 48 h, apoptosis was evident. The results suggest that 5-Fu can induce apoptosis in Eca-109 cells.