There are many reasons for dark green stools, such as food, intestinal indigestion, acute gastroenteritis, etc. 1, the color of the food itself, some of the pigments contained in the food will affect the color of the stool, such as eating a lot of vegetables, or the gastrointestinal acidity is high, will make the stool dark green. 2, intestinal indigestion, because of their own improper diet, disrupt the balance of the intestinal flora, resulting in stool color change.