Stool comes in a range of colors. All shades of brown and even green are considered normal. Only rarely does stool color indicate a potentially serious intestinal condition. Stool color is generally influenced by what you eat as well as by the amount of bile â a yellow-green fluid that digests fats â in your stool. As bile pigments travel through your gastrointestinal tract, they are chemically altered by enzymes â changing the pigments from green to brown.