消化道出血是指血液由于各种原因经过胃肠道丢失，常见的病因包括消化道本身的炎症、机械性损伤、血管病变、肿瘤、胃肠道邻近脏器疾病等。不同原因导致的消化道出血其临床特点有显著差别。因此，充分认识消化道出血原因和特点有利于诊断和治疗。消化道出血分类方法很多，主要根据消化道出血的病因进行分类。

Etiology and characteristics of gastrointestinal bleeding  SUO Jian. Department of General Surgery，the First Hospital of Jilin University, Changchun 130021，China
Abstract    Gastrointestinal bleeding is the loss of blood from the gastrointestinal tract. The common cause of the disease includes inflammation of the digestive tract itself, mechanical injury, vascular lesions, tumors and extra-gastrointestinal tract diseases, etc. Different causes of gastrointestinal bleeding are different significantly. Therefore, the realization of the etiology and characteristics is essential for surgeons to diagnosis and treat the disease. The etiology of gastrointestinal bleeding has been discussed and summarized in the paper.