下消化道出血主要指病人从直肠排出鲜红或暗红色血液,一般认为血系来自回肠或结肠。这样的判断在多数病人中是正确的,只有很少数病人可因上消化道的大量出血而表现为直肠排出红色血液。在这种情况下,常有大量失血的临床征象及血清尿素氮升高。相反地,下消化道大量出血是较少见的。出血的病因是很复杂的,国内外资料统计各种便血病因中,其发生率有较大的差异,可能与饮食的习惯不同有关。我国人饮食中纤维素较多,粪便 Lower gastrointestinal bleeding mainly refers to patients discharged from the rectum bright red or dark red blood, generally believed that blood from the ileum or colon. This judgment is correct in most patients, only a very small number of patients may be manifested by the rectal discharge of red blood due to massive bleeding in the upper digestive tract. In this case, there is often a large number of clinical signs of blood loss and elevated serum urea nitrogen. Conversely, the lower gastrointestinal bleeding is less common. The etiology of bleeding is very complex, statistics of various blood samples at home and abroad in the incidence of blood in the larger differences may be related to the different eating habits. My diet more cellulose, manure