Reviewed By: Pramod Kerkar, MD, FFARCSI

Our body eliminates toxins in the form of waste matter. Stools that are passed out as waste are normally yellow to brown in color, however, sometimes they may appear different. This article deals with 7 reasons for passing out green colored stools.

Normal color of the stool usually varies from light yellow to dark brown, depending on the diet and the habit of passing stools. It can vary from dark yellow to brown on daily basis as per the amount and type of the food eaten by the person. It is usually not a health risk if the color of the stool remains within this range.

While green colored stools may be simply due to diet or drugs, some causes may need attention. It is not a big concern if an isolated stool color change is observed but if it continues to occur and with unusual symptoms, it must be investigated. Any change in the color of stool is usually associated with symptoms like abdominal pain, nausea, diarrhea, dizziness or vomiting. Hence it is necessary to know the reasons for passing out green colored stools.

7 Reasons for Passing Out Green Colored Stools

7 Reasons for Passing Out Green Colored Stools

Here are the top 7 reasons for passing out green colored stools.

#1. Medications

Some medications can be responsible for passing out green colored stools.

Patients who have had spinal cord injury or bowel cancer tend to have slow bowel movements and smelly stools. It also causes the stool to lose its water content, which makes it hard to excrete out. Individuals suffering from colostomy and ileostomy also suffer from the same fate. Drugs like Derifil, Nullo and other herbal supplements are prescribed to treat such medical conditions. These drugs increase the motility of the bowel and reduce the smell of feces and urine. These drugs have chlorophyllin, a derivative compound of chlorophyll, in them which cannot be digested by humans and therefore, is removed as it is in the stool. This is one of the 7 reasons for passing out green colored stools.

  • Antibiotics – Antibiotics like fluoroquinolones, macrolides or cephalosporins can cause death of normal flora of the gastrointestinal tract. In such cases, some bacteria that cause degradation of urobilinogen, the component that gives stool its characteristic brown color. Thus the color of the stools changes to green. These drugs are also the commonest reasons for passing out green colored stools.
  • NSAIDs and Contraceptive Drugs - Some contraceptive drugs are known reasons for passing out green colored stools. Similarly, non-steroidal anti-inflammatory drugs (NSAIDs) like Indomethacin for treating inflammation, also changes the color of stool to green.
  • Laxatives - People suffering from constipation use laxatives to ease out the mobility of stools. When laxatives are consumed in excess amount, it can speed up the bowel movement and hence may hamper the digestion process. As a result of this, the stools are loaded with bile juice imparting the green color. This is yet another reason for passing out green colored stools.
  • Vitamins and supplements - Iron and fiber supplements generally change the color of the stools to green.

#2. Gastrointestinal Diseases

Gastrointestinal disorders are commonest one of the 7 reasons for passing out green colored stools. Some of the common conditions

  • Crohn's Disease - It is a type of inflammatory bowel disease, causing inflammation of the intestine. It minimizes the absorption of water and hence increases the speed of bowel movements with hyper secretion from some glands along the way, ultimately resulting in a speedy bowel movement through the gastrointestinal tract. When there is an inflammation along with diarrhea, the bile cannot emulsify fat in the intestine and is rapidly passed out of the body, turning the stools into green color. The green color is imparted due to the presence of large amount of bile juice in the stool.
  • Celiac disease – In celiac disease, the body shows an abnormal immune response to the gluten in the food. Gluten is a type of protein found in wheat, rye, or barley. The body is unable to digest gluten and is normally excreted out of the body. However, when the body develops an immune response against gluten protein, it damages the villi present on the lining of the intestine, responsible for the absorption of nutrients as well as bowel movement. When the villi get damaged, the absorption of food decreases through the intestine and it is expelled out of the body unabsorbed along with the bile juice. Hence, the color of the stool turns green and watery in nature because of the presence of bile juice in stools. This is one of the commonest reasons for passing out green colored stools.

#3. Infections

Another one of the 7 reasons for passing out green colored stools are infections. These bacteria, virus and parasites act on different parts of the gastrointestinal tract and hence results out into various symptoms and in turn, cause different types of diseases. The common symptom, i.e. green colored stools exists in all these disease types.

  • Salmonella - Salmonella is a bacterium well known for causing typhoid fever, food poisoning and gastroenteritis. The symptoms usually appear in three days after the actual infection. The symptoms include abdominal cramps, diarrhea and vomiting. It is due to contaminated water or food that the organism enters the human body. The diarrhea caused by this organism makes the bowel movements swift and hence causes bile to be excreted along with the stools. Hence, because of the presence of bile in the stools, its color changes to green. This is one of the commonest reasons for passing out green colored stools.
  • Shigella - Shigellosis is a disease caused by a bacterium called as Shigella. The symptoms of Shigellosis start appearing after 5 to 7 days of infection. The very first visible symptom is diarrhea. If diarrhea is severe, then the color of stools is usually green. It may be associated with stomach pain, fever and even bloody stools, in which case, immediate medical attention is needed.
  • Giardia lamblia - Giardiasis is a disease caused by a parasite called as Giardia lamblia. In this disease, the stools turn greasy in nature and can be one of the reasons for passing out green colored stools. Abdominal cramps, nausea, loss of appetite are some of the associated symptoms experienced in Giardiasis.
  • Norovirus - Norovirus is transferred from one person to another via direct contact. It also causes diarrhea with green colored stools because of the presence of bile juice in it. Bile juice may also be present in the vomiting, making it green in color as well.

#4. Dietary Intake

Consumption of certain foods and drink is one of the known 7 reasons for passing out green colored stools. Although the color of stools turns green, which is normal, it is not a matter of much concern as it doesn't occur with alarming symptom such as stomach pain, diarrhea, vomiting etc. As the food or drink, responsible for causing green colored stools, excrete out of the body, the color of the stools change back to normal.

Following are some of the example of food types that cause a change in the color of the stools.

  • Green leafy vegetables - Broccoli, spinach, kale are some of the green vegetables that have high amount of chlorophyll present in them. As chlorophyll is not digested in the body and is readily excreted out, it causes the color of the stool to change to green. People on special diets do tend to drink juice with a lot of green food in it, which can be some of the common reasons for passing out green colored stools.
  • Fruits - Blueberries, grapes and some other similar fruits impart green color to the stool when digested in the gastrointestinal tract. The amount of fruit consumed determines the color of the stool. When consumed in excess quantities, might give a dark blue to green color to the stools.
  • Coffee and Spices - Large intake of spices and coffee can also change the color of the stool to green. It happens due to the laxative effect of these food items. These cause the excretion of the bile in large quantities in the gastrointestinal tract and cause incomplete degradation of bile. The presence of bile in the stools is a reason for passing out green colored stools.
  • Food colors - There are some food items and drinks that have food colors added to them. They are not usually digested and broken down in the gastrointestinal tract. Food colors is yet another reasons for passing out green colored stools. Cakes, jellies, cream biscuits and some drinks do have a lot of food color added in them to make them look appealing. It is not a concern until you notice any symptoms that may make your body feel uneasy.

#5. Pregnancy

Green stool is quite common during pregnancy and it can be due to a number of reasons. The most common one is high fiber diet and slow bowel movement. A high fiber diet is usually prescribed to prevent constipation in women as the food moves slow in the intestines of pregnant women. The food that has a lot of green chlorophyll in it will cause the color of stool to turn green as all other waste products will be absorbed to the maximum except chlorophyll. Chlorophyll turns the color of the stool green.

Hence, pregnancy is one of the top 7 reasons for passing out green colored stools.

Pregnant women are also on vitamins and supplements so as to provide proper nourishment to the baby. Also, the presences of the any other condition or drugs causing green colored stools can cause more problems.

#6. Anal fissure

Anal fissure is a small tear in the skin at the opening of the anus and it causes constant irritation. Pain occurs while passing out stools, due to which, people often resist going to the washroom and hence develop constipation. This is again an important of the 7 reasons for passing out green colored stools.

Anal fissure is often confused with hemorrhoids as the pain is somewhat similar and is in the same region of the anus. Although the fate is same, the stools are red in color in hemorrhoids as blood passes out along with the stools.

#7. Bone Marrow Rejection

Bone marrow transplant rejection is one of the most important 7 reasons for passing out green colored stools. There are greater chances of diarrhea and abnormal stools, as a result of the bone marrow transplant rejection. Due to rejection, the gastrointestinal tract functions are impaired and it gets upset. It, as a result leads to an increase in the bowel movements in the intestine. Hence, the degradation and absorption of food and bile salts doesn't occur properly in the intestine and as a result of which the color of the feces turn, green.

Conclusion

While green colored stools can occur due to various reasons, if they continue for long, it is worth seeking medical opinion. Also, if green colored stools are accompanied with abdominal pain, nausea, diarrhea, dizziness or vomiting, bloody stools, fever or any unusual symptom, if must be reported at once. While these 7 reasons for passing out green colored stools are the commonest, the physician would like to investigate for proper diagnosis, based on which treatment can be planned.

Also Read:

Pramod Kerkar

Written, Edited or Reviewed By:

, MD,FFARCSI

Pain Assist Inc.

Last Modified On: May 23, 2018

This article does not provide medical advice. See disclaimer

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