Diarrhea stools appear red possible causes are, dietary structure changes, gastroenteritis, digestive tract tumors, etc. First of all, if you eat red dragon fruit, watermelon, red heart radish, etc., these foods contain red pigment, in the stomach after digestion, out is still red, which generally belongs to the normal phenomenon do not worry too much. Secondly, if the usual unclean diet, and like to eat spicy, stimulating things, smoking, drinking seriously, bad mood, too much stress will appear gastroenteritis, with gastroenteritis will appear upper gastrointestinal bleeding, red blood or mucus in the stool. Then if long-term improper diet, emotional depression, accompanied by diarrhea, abdominal pain, abdominal distension, etc. may appear tumors, fecal occult blood will be positive, diarrhea, red in the stool, the specific situation needs to do gastroscopy and treatment to determine.