0　引言　　癌化学预防 (ｃｈｅｍｏｐｅｒｅｖｅｔｉｏｎ)是指用化学药物作用于肿瘤发生的某些环节 ,预防恶性肿瘤的发生。不少食物来源的化合物和微量营养元素可阻断食管癌的发生和发展 ,如异硫氰酸盐、维生素Ａ类化合物等。近来 ,随着研究的深入 ,中药对食管癌的阻断备受关 0 Introduction Cancer chemoprevention (chemoperevetion) refers to the use of chemical drugs in some aspects of tumorigenesis, prevention of malignant tumors. Many food sources of compounds and micronutrients can block the occurrence and development of esophageal cancer, such as isothiocyanates, vitamin A compounds. Recently, with the deepening of research, the block of esophageal cancer by traditional Chinese medicine is closely related