The Short Answer from physician experts
Q: My poop is bright green. Should I be concerned about the color of my stool?
If your stool is a color other than brown, rest assured that it’s usually a result of what you recently ate. Leafy greens can make your stool look green, while red fruits and veggies (like beets), artificial food coloring, and some medicines and supplements also can alter the hue of your poo.
What should raise concern is bright red blood in your stool. This can indicate a polyp in your large intestine or rectum, rectal inflammation, diverticulosis, or even colon cancer. A tarry black stool can signal the presence of older blood from higher up in your digestive tract. This isn’t always a bad thing, but sometimes, it’s a result of a stomach or upper gastrointestinal ulcer.
Most diet-related color changes will disappear in a day or two. If the unusual colors persist, or if you have constant urges to have a bowel movement or to vomit, or if stomach cramps persist, see your doctor.