The color of your stool generally reflects what you have eaten and how much bile is in your stool. Bile is a yellow-green fluid excreted by your liver and aids digestion. As bile travels through your gastrointestinal (GI) tract it changes to a brown color.

When you have IBS you might be accustomed to changes in stool size and consistency, but a change in color might be initially alarming. In many cases, it is unlikely that it is a change that should cause concern.

However, for many people, anxiety can be an IBS trigger. So worrying about stool color can actually trigger your IBS symptoms.

Any major change in the color, consistency, or amount of your stool that continues for several days is worth discussing with your doctor. If your stool is black or bright red, it may be an indication of blood.

  • Black stool could indicate bleeding in the upper GI tract, such as the stomach.
  • Bright red stool could indicate bleeding in the lower intestinal tract such as the large intestine. Bright red blood could also come from hemorrhoids.

If you have black or bright red stool, seek medical attention promptly.

Yellow stool concerns

A few yellow stools are typically of little concern. However, you should see a doctor if your yellow stool is accompanied by any of the following symptoms:

There are a number of reasons your stool might be yellow, whether you have IBS or not, including:

  • Diet. Eating certain foods like sweet potatoes, carrots, or foods high in yellow food coloring can turn your stool yellow. Yellow stool could also indicate a diet that is high in fats.
  • Pancreas problems.If you have a condition that affects the pancreas — such as pancreatitis, pancreatic cancer, or a blockage of the pancreatic duct — you might not be able to properly digest food. Undigested fat can make your stool yellow.
  • Gallbladder problems. Gallstones can limit bile reaching your intestines, which can turn your stool yellow. Other gallbladder disorders that can cause yellow stool include cholangitis and cholecystitis.
  • Liver problems. Hepatitis and cirrhosis can limit bile salts for food digestion and nutrient absorption, turning your stool yellow.
  • Celiac disease. If you have celiac disease and eat gluten, your immune system can damage your small intestine, resulting in an inability to absorb nutrients. One of the symptoms is yellow stool.
  • Giardiasis. The symptoms of an infection of the intestinal tract by a parasite called giardia include diarrhea that is commonly yellow.

Yellow stool is usually a reflection of diet and not specifically attributable to IBS. Although it is not initially a cause for concern, it could be caused by underlying health conditions.

If you notice that your stools have been yellow for a few days or are accompanied by other troubling symptoms, see your doctor. Treatment will be based on the underlying cause that is triggering the yellow stool.

If your stool is bright red or black, get prompt medical attention.