Q: What causes bowel movements to change color?
Dr. Dave says: As most people know, your stool color can change a lot from day to day. The color is generally influenced by what you eat as well as by the amount of bile (a yellow-green fluid that your body produces to digest fats) in your stool. As bile pigments travel through your gastrointestinal tract, they are chemically altered by enzymes, which change the pigments from green to brown. If the stool is making it’s way through your intestines very quickly (i.e. if you have diarrhea), the enzymes won’t have time to act on it, so the colour can be quite green. We often see this in kids, and while it causes parents a lot of concern, it’s rarely something to worry about.
So, how can you tell if there’s something wrong based on the color? In general, any and all shades of brown are considered “normal.” Some foods, such as beets and some food coloring can produce pretty interesting hues. Even certain medications, such as Pepto-Bismol, can turn your stools quite black, so if you are concerned and are going to ask your doctor, think about what you might have eaten the day or so before—it will be helpful information for them.