When you eat blood sausage or other animal blood, the black stool will return to normal in about 1-2 days, and will not exceed 3 days at most. The black stool caused by eating animal blood has no special odor, the stool is formed, and the bowel habits are normal, usually 1-2 times a day or once every other day, and the volume of stool is the same as normal. If you stop eating animal blood for more than 3 days and still find bloody or black stools, you need to pay attention to rule out the presence of gastrointestinal bleeding. It is more common to see upper gastrointestinal bleeding, such as bleeding from peptic ulcer or bleeding from acute gastritis. If necessary, patients are advised to go to the hospital to complete an electronic gastroscopy to assist in the diagnosis and treatment. Black stools may also occur if special medications such as bismuth or iron are taken at the same time, and specific attention needs to be paid to identify them.