According to Query 39 Health Network, black sesame is a nutritious food, which contains a lot of fat, protein, sugar, vitamin A, vitamin E, lecithin, calcium, iron and chromium. It has the functions of invigorating stomach, protecting liver, promoting the growth of red blood cells, delaying aging, etc., and can also increase melanin in the body, which is beneficial to hair growth. The skin of black sesame contains a lot of natural melanin, which cannot be metabolized by the human body in the digestive system. Therefore, after eating, natural melanin will be excreted together with food residue. When black sesame seeds are consumed too much, because there are more melanin, the color of stool will change black, and black will be mixed with feces. Therefore, it is normal to eat black sesame seeds and have black stools. After black sesame seeds are metabolized by the human body, the stools will return to normal. However, if the stool is tarry, or accompanied by severe abdominal pain, diarrhea and other symptoms, then you should go to the hospital in time to avoid being caused by gastrointestinal bleeding.