Green Stool

Stools (also called poop, feces) are the waste products of digestive system that are excreted out of the body through an anal opening. The amount, color and quality of stools are the characteristic features that are indicative of general condition of the digestive system. Any deviation of these features from normal is an indication of an abnormality of the digestive system. The change of color of stools to green is the topic of discussion in this article.

There is no particular color of normal stools. There is a range of colors which are considered normal. Almost all shades of brown and sometimes, even green and other colors are considered under normal stools. In rare cases, the changed stool color is an indicative of serious illness of the digestive system. The most common color of stools is the shade of brown color. This brown color is imparted to stools by the fluid like pigment called bile (which is secreted from gall bladder into the foremost part of the intestine, for fat absorption). The bile when enters the intestine is green in color, during its course through the digestive system it is absorbed and broken down ultimately changing to brown color, which is imparted to feces mainly by it.


The color of stools is most commonly influenced by:

  • The food that is taken

  • The amount of bile excreted by body in stools

  • The condition of digestive system

  • General health condition of the body

  • Medication that are taken

  • Supplements that are taken


If the color of stools is changed to green, it is not necessarily considered as an alarming condition. It may be normal in some conditions and may appear for a short time, while it can be an indication of an abnormality in some other conditions and may persist until the problem is cured.

Generally speaking, if the green stools are present alone, without any additional signs and symptoms then most probably the cause is not dangerous and is temporary and will be resolved easily. But if the green stools are present with other signs and symptoms, then detail check up is recommended to find out the abnormality causing the green stools.

Predictable conditions causing green color of stools:

  • Intake of huge amount of green vegetables like broccoli, cabbage and lettuce etc causes green stools. However they cause green stools because the amount of these vegetables, that are taken is more than the amount that the body can deal.

  • Intake of good quantity of food containing green food color like ice pops, green colored flavored drink and green colored topping on cakes etc can also cause the green stools.

  • Intake of certain vitamins and supplements like iron etc results in green stools. Although these substances are not green but they undergo harmless reactions inside the digestive tract that results in the appearance of green color of the stools.

  • Intake of laxatives also causes green stools due to quicker movement of food through digestive system. This quick movement does not give enough time for green bile’s break down thus causing green stools.

  • Severe diarrhea also causes green stools because the movements of digestive system are increased in this case. Due to these fast movements, the food is passed quickly through the digestive system. This quick movement does not give enough time for green bile’s break down thus causing green stools.

  • Intake of some medicines like contraceptive pills, indomethacin and some antibiotics also causes the green stools as they are one of the side effects of some drugs.

  • Stress results in diarrhea that can cause green stools.

  • Meconium dark green colored stool passed by the newborn is called meconium.

  • In all the conditions mentioned above, the appearance of green stools is transient and is not considered harmful most of the times.

Some common diseases causing the green stools:

  • Patient undergone bone marrow transplant

Because of host versus graft reaction

  • Infections by certain bacteria

Like Salmonella causes green stools

  • Infection by certain parasites

Like Giardia

  • Irritable bowel syndrome, ulcerative colitis and crohan’s disease

All these diseases prevent the breakdown and absorption of bile in the intestine thus causing green stools

  • Food poisoning

In all the conditions mentioned above, the green stools are presented with other signs and symptoms of the disease and thus are considered harmful.