Green poop: What stool color can indicate about health

Question: My poop sometimes turns green. What can cause green poop? What do changes in stool color mean about your health?

Answer: Temporary changes in stool color from the usual brown most often do not indicate a serious medical problem. But certain color changes may require medical attention, especially if you have other symptoms.

Green poop

Intermittent green stool in someone who otherwise feels fine is usually related to eating dark green vegetables, such as spinach and kale. Another reason for green poop is the rapid passage of green bile from the small intestine when a person has diarrhea. Medications, including bismuth subsalicylate (Pepto-Bismol), iron supplements, and some antibiotics, may also result in greenish colored stool.

Very pale brown stool

Pale stools can be a sign of liver or gallbladder conditions. If insufficient bile is produced by the liver or there is a blockage of the bile duct, the bile salts that aid digestion can be greatly reduced. Examples of conditions that can lead to pale stools include hepatitis, cirrhosis, and gallstones. People with pale stools due to one of these problems often have jaundice (yellowing of the skin and whites of the eyes) and cola-colored urine.

Yellow stool

Excess fat in poop can give stool a yellow color. An extremely high-fat diet might cause the color change. However, if stool is yellow, greasy, floats in the toilet bowl, and smells bad, that probably means there is a problem with fat absorption. This can occur from liver disease, pancreatitis, a bile or pancreatic duct blockage, or a small intestine condition such as celiac disease. Some infections such as giardiasis can also cause yellowish stool.

Red poop

Red poop always raises the possibility of blood in the stool. Small amounts of blood in the toilet bowl or on toilet paper are most often from hemorrhoids. Larger amounts of bright red blood should always prompt an immediate call for medical advice. If a person also has lightheadedness, then emergency evaluation is needed. Anyone with persistent or recurrent rectal bleeding, even in minimal amounts, should make an appointment with their doctor. Some red foods such as beets and tomatoes and red food dyes can also cause red poop.

Black stool

Tarry, foul-smelling black stool can indicate bleeding from the stomach or upper small intestine. Stomach acid and digestive enzymes convert blood from a red color to black. This always requires immediate medical attention. Iron supplements, bismuth subsalicylate (Pepto-Bismol), and activated charcoal may blacken stool. Blood sausage, blueberries, and black licorice are also possible causes.