Patients with black, dry and hard stools, consider three factors, as follows: 1, slow emptying of the stool: eat a lot of greasy, high protein food, slow emptying of the stool, there will be black, dry and hard stools, the smell is generally smelly. 2, improper feeding: consumed certain drugs, food and stool staining, such as taking bismuth, iron, Chinese medicine, or eaten animal blood, animal offal, there will also be stool Color change. 3, gastrointestinal bleeding: be alert to the occurrence of gastrointestinal bleeding, generally adults with daily bleeding > 5mL, positive fecal occult blood test, the naked eye view is still yellow, but if the amount of bleeding > 50mL, it can appear black stool, tarry stool, so when there is black, dry and hard stool, consider the increase in bleeding, but the bleeding is relatively small, bleeding is relatively slow. There are many clinical reasons for the occurrence of bleeding, such as peptic ulcer, ruptured esophagus-fundus varices, gastrointestinal tumors, erosive gastritis, and many other factors, so it is important to seek medical attention in a timely manner, make a clear diagnosis, and give appropriate treatment to avoid delaying the condition.