Green stool

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 14, 2015
StartSymptomsGreen stool

Bowel movements are an unavoidable part of everyone's lives. While most bowel movements are a healthy brown color, it's not uncommon for there to be a range of other colors that show up in a person's stool. There are several factors involved in discoloration of the stool, including diet, the amount of bile in the digestive system, and the amount of time the stool remained in the body. Green stool is fairly common, and is usually not a cause for concern.


Definition & Facts

Bowel movements are a natural part of the human digestive process; or actually, it's the end result. After the body absorbs the nutrients it needs from the food it's digested, the leftovers are expelled through the bowels as the stool. The stool is whatever is left after nutrient absorption, and is normally a shade of brown.

This pigmentation is normally caused by a mix of dead blood cells and waste from bacteria that lines the intestines. It's also influenced by the amount of bile that is present in the intestines, specifically the small intestine. Here, bile is usually green. If the stool is passed through the bowels too quickly, this could cause the greenish color.

This is sometimes referred to as “rapid transit” or “decreased colonic transit time". Stool that is passed through the bowels too quickly can be green; however it can also be other colors, depending on a variety of factors.


One of the most common causes of green stool is food choices. There are many foods which contain green food dye, and sometimes it does not get processed properly, resulting in a green hue in the stool. Surprisingly, foods colored with purple colorants can also cause a green tinge in the stool; these include popsicles, gelatin, or fruit drinks.

The Green stool can also be the product of a diet rich in leafy greens, such as kale, broccoli, or other green vegetables. Dark leafy greens contain chlorophyll, a molecule that absorbs sunlight into plants and causes the green pigmentation. This can still be present in the stool. Besides food, there are a few other things that can cause green colors to appear. It can also be caused by iron-rich food or iron supplements. Antibiotics, especially strong ones, can clear out the intestines, which in turn also clears out the bacteria that causes the brown hues.

Green stool can also be caused by parasites or bad bacteria, like salmonella or a norovirus. These can cause diarrhea. Diarrhea is a major cause of green stool; this causes the stool to pass through the intestines and bowels too quickly. Stool that passes through too quickly does not have time to turn brown like a normal bowel movement.

Infants, babies, and children experience green stool more frequently than adults. Green stool is a normal occurrence for breast-fed infant, and is actually very normal during the first few days after delivery. As children age, the occurrence of green stool fades; when it occurs in children, it's normally food related or could be caused by ingesting some sort of non-food item, such as crayons, markers, ink or paint.

When to see a doctor

Green hues in the stool is rarely a cause for panic. There is not much reason to see a doctor. However, if the green stool is not the only color that is showing up, and there are other difficulties with bowel movements, it's wise to have a check up with a doctor. Long lasting discoloration of the stool could indicate a more serious issue; or if there are any symptoms present, including abdominal pain, nausea, or vomiting.

If any of these symptoms occur with green stool, it may be smart to seek emergency medical attention. It could signal some sort of infection or virus, which need to be treated as soon as possible to avoid dehydration or worsening sickness. Seeking emergency help is especially important if someone is experiencing dehydration from diarrhea; this means the bowels are moving too quickly through their systems. This can be dangerous and may need to be stabilized with fluids.

For children, if there is a concern that discoloration of the stool is caused by ingesting a non-food item, it's wise to contact poison control or the child's pediatrician. If there is any suspicion that bowel changes or colors are signaling something worse, make an appointment with a doctor to have a check-up and discuss any concerns.

Treatment & Therapy

Treatment for green stool really only involves treating whatever may be causing it. If it's something like an infection, bacteria or parasite, it may be treated simply by a round of antibiotics, or may require a stay in the hospital if there is severe dehydration. Most of the time, resting and plenty of fluids will be enough to recover from these issues.

If the cause if from something ingested, there's really not much to do but wait it out. If discoloration occurs frequently as a result of dyes, such as those in candy or deserts, simply laying off these foods can make the green fade. If it is a result of veggie-rich diet, there is not much to be done, and in this case, there is really no reason to change anything, as it's a sign of a nutrient rich diet and healthy bowel movements. To determine if something is causing the discoloration simply cut out this food for a few days and see if there is an improvement.

Prevention & Prophylaxis

If preventing green stool is desired, then its best to just avoid all foods listed above. However, this would mean avoiding leafy greens, which are an important thing to eat every day for a nutritious diet. Avoid things like iron supplements unless necessary, and anything with artificial colors which could cause color changes in the bowels.

Don't take antibiotics unless absolutely necessary, to allow the good bacteria to remain in your gut and avoid discoloration. In general, having a healthy, well-rounded diet with nutrient rich foods, plenty of water and regular exercise will help avoid any problems with bowel movements and digestive health.

Books about Bowel movements at