Yesterday, my stool color was bright green. Should I be concerned?

Answer From Michael F. Picco, M.D.

Stool comes in a range of colors. All shades of brown and even green are considered typical. Only rarely does stool color indicate a possibly serious intestinal condition.

Stool color is generally influenced by what you eat as well as by the amount of bile — a yellow-green fluid that digests fats — in your stool. As bile travels through your digestive tract, it is chemically altered by enzymes, changing the colors from green to brown.

Ask a healthcare professional if you're concerned about your stool color. If your stool is bright red or black — which may indicate the presence of blood — seek medical attention right away.

Stool quality What it may mean Possible dietary causes
Green Food may be moving through the large intestine too quickly, such as due to diarrhea. As a result, bile doesn't have time to break down completely. Green leafy vegetables, green food coloring, such as in flavored drink mixes or ice pops, iron supplements.
Light-colored, white or clay-colored A lack of bile in stool. This may indicate a bile duct blockage. Certain medicines, such as antacids with aluminium hydroxide, large doses of bismuth subsalicylate (Kaopectate, Pepto-Bismol), other antidiarrheal drugs, and barium, which is used in X-rays.
Yellow, greasy, foul-smelling Excess fat in the stool, such as due to a malabsorption condition, for example, celiac disease. Fatty foods such as deep-fried foods, and sometimes the protein gluten, such as in breads and cereals.
Black Bleeding in the upper gastrointestinal tract, such as the stomach. Iron supplements, bismuth subsalicylate (Kaopectate, Pepto-Bismol), black licorice.
Bright red Bleeding in the lower intestinal tract, such as the large intestine or rectum, often from hemorrhoids. Red food coloring, beets, cranberries, tomato juice or soup, red gelatin, or drink mixes.

From Mayo Clinic to your inbox

Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.

To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.

Oct. 10, 2024 See more Expert Answers

See also

  1. Mucus in stool: A concern?
  2. Narrow stools: Should I be concerned?
  3. Undigested food in stool
  4. White stool: Should I be concerned?