Eating stinky tofu black stool may be a normal physiological phenomenon, may also be due to chronic gastritis, peptic ulcer, esophagitis and other diseases caused by the upper gastrointestinal bleeding. 1. Physiological factors: stinky tofu contains a certain amount of melanin, if you eat too much, it will be discharged with the stool, resulting in black stool. This is usually a normal physiological phenomenon, patients usually do not have obvious discomfort, after stopping eating, the stool will gradually return to normal. 2. Pathological factors: if the patient stops eating stinky tofu for a period of time, the stool is still black, or accompanied by abdominal pain and bloating, acid belching (burp), loss of appetite, nausea and vomiting and other discomforts, it should be considered as a result of disease, such as chronic gastritis, peptic ulcer, esophagitis, etc., in the triggering of the upper gastrointestinal tract bleeding, which can lead to black stools. In addition, if you are taking iron, bismuth and other drugs while consuming stinky tofu, you will also experience blackened stools. If the patient has long-term or repeated black stools with discomfort, it is recommended to consult a doctor in time to identify the cause of the disease and carry out targeted treatment to avoid delaying the condition.