Dark Green Stool

By Dr. Ritu Krishnatreye, BHMS
Dark green stool

The color of stools are an indication whether you are suffering from an underlying disease. They may also be a result of something you recently ate.

Stools can turn dark green in color due to a number of reasons, including diet, medications or some health issues. 

4 Causes of Dark Green Stool

1. Caused by what you eat

  • The dark green color of stools may be a result of eating green colored food items, like green leafy vegetables (spinach, lettuce or broccoli).

  • Sometimes, the color of the fecal matter turns green due to artificial colors commonly added to fruit juices, milk products, cereals, ice creams and milk products.

  • Some iron containing foods, when taken in large quantities, can also turn the color of stools to green.

Usually, artificial colors result in bright green color stools, whereas the stool color after ingestion of naturally green foods is usually darker in color. 

The color of the stools may remain dark green for four to five days after the ingestion of above mentioned foods and is nothing to worry about, as long as there are no other associated symptoms.

2. Caused by medications or supplements

Certain medications and supplements can give green color to the stools.

  • Laxatives, iron supplements and medications and supplements containing chlorophyll may cause dark green stools.

  • Vitamins and minerals that are artificially colored or those containing sorbitol or fructose sugar can affect the process of digestion and speeds up the peristaltic movements in the intestines. This results in fast movement of fecal matter from the colon, resulting in green stools. 

Again, this is not of a matter of serious concern.

If you are concerned, talk to your doctor about changing the brand of medication or supplement. You may also avoid eating foods that contain artificial flavors or fructose.

3. Caused by an illness

  • Stools may continue to be green due to any bacterial or parasitic infection.

  • Food poisoning by giardia, salmonella or rotavirus can cause infection and result in dark green stools.

Other associated symptoms include diarrhea, nausea, abdominal pain, fatigue and at times fever. Consult your health care provider if you suspect the symptoms of infection or food poisoning. 

4. Caused by a decrease in bowel transit time

Bile is an important part in the process of digestion. While it is true that it gives a green color to stools, intestinal bacteria and enzymes that should be present in colon turn it brown.

However, any condition that decreases the transit time of stool through the bowel may not give intestinal bacteria enough time to do their work. This can lead to green stools.

The conditions that may affect the bowel transit time include:

  • Food allergies
  • Fructose malabsorption
  • Lactose intolerance
  • Ulcerative colitis
  • GERD

All these health conditions are chronic in nature and require an adjustment in diet and lifestyle, and should be monitored by a doctor.

Dark Green Stools and Constipation

It is possible to have dark green stools and yet struggle with constipation.

If this is the case, increasing daily fiber intake from vegetables, fruits, whole grain products and products containing bran is usually a first step to constipation relief.

If you are like some people and extra fiber seems to increase constipation problems, you may want to consider taking a daily magnesium supplement

Magnesium is a natural osmotic laxative that draws extra water into the colon, helping to hydrate stools. A moist stool is soft, slick and generally easy to pass.

Since most of us don’t get enough magnesium in our diet, taking a daily magnesium supplement may result in numerous health benefits

Conclusion, dark green stool

As we have discussed above, it is important to be in tune not only to what is going on in your body, but also with what comes out. Your bowel movements can be barometer of overall health.

Paying attention to minor details such as the color of your stool can help in identifying an illness at an early stage.

(Return from Dark Green Stool to What is Constipation)

Like what you have found?
Please Spread the Word!



Please share your comments in the box below.