Eating a lot of beef can lead to black stools. Why do stools turn black? Part of it is because there is bleeding in the digestive tract, such as the stomach, duodenum, esophagus, these upper gastrointestinal tract if there is bleeding, there will be tar-like stool, that is, black stool. 2, diet and some drugs can also lead to, diet, such as a large number of animal offal, pig blood, duck blood, chicken blood, etc., and is to eat a lot of beef, because these animal products offal rich in iron, iron through the body can become Black iron sulfide, resulting in black stools. So a lot of intake of beef, an iron-rich animal food, will lead to black stools, stop eating too much beef stools will become normal, there are other vegetables such as spinach will also have this situation. So when eating a lot of beef, spinach and other animal offal. All of them may have darkened stools.