Red stool but not blood is caused by dietary factors. Under normal circumstances, the color of stool should be dark yellow, which is mainly caused by bilirubin mixed with food residues, resulting in fecal staining. The color of stool can also be affected by diet, the intake of food containing natural pigments in the diet, due to the inability of the natural pigments to be absorbed by the human body, which will lead to a change in the color of the stool. Red color in stool but not blood is common in dietary problems, such as eating red dragon fruit, watermelon, tomatoes, jujubes, red peppers, red pigment in these foods will be accompanied by food residues and feces together with the excretion of the feces, so the formation of red color in the stool. Because of diet-induced red stools, the color will be evenly distributed in the feces, and the shape and nature of the feces will not change, while there is no bloating, abdominal pain, diarrhea and other manifestations,