What is the cause of black hard stool?

1, constipation

patients due to stool in the intestinal tract for a long time, which will be gradually absorbed water, with less water, stool will gradually harden, color will gradually deepen, and finally appear stool black hard situation.

2, intestinal obstruction

patients with intestinal obstruction, due to stool can not be discharged in time, water will be absorbed by the intestinal tract, and finally only black hard stool residue.

3, intestinal

cancer patients due to the influence of tumor, intestinal patency will be blocked, when the tumor surface cells fall off necrosis and feces mixed, will cause blood stool, plus feces stay in the intestinal tract for a long time, water will be absorbed, under the action of intestinal bacteria, blood will be decomposed into black iron sulfide, so that stool becomes black hard.