What Are the Causes of Green Feces?

Various medical conditions and dietary foods can alter the color of feces. Although green feces may look scary, it is most often harmless. Usually green feces is not a cause for concern and is simply caused by dietary intake. When green feces is accompanied with other medical symptoms or is persistent, a doctor should be seen.

Infants

Sometimes breast-fed and formula-fed infants eliminate green feces. In the absence of other symptoms, it is quite normal and is a response to eating a liquid diet or a baby formula that contains iron. Green feces that is accompanied with yellow skin, skin rashes or constipation may be caused by jaundice or food allergies and warrant a trip to the doctor's office.

Food

Most cases of green feces are caused by food items that we ingest. Eating a lot of green vegetables or a lot of foods that contain green food colorings causes green feces. In food-related green feces, once the perpetrating foods are eliminated from the bowels, feces return to a normal color.

Supplements

Ingesting large amounts of supplements can turn the feces green. The most common supplement culprit is iron. The body cannot process large amounts of iron, so the body excretes iron salts to eliminate the excess amounts. Iron salts color the feces green. Other supplements that can turn feces green are chlorophyll and green algae. When supplements are discontinued or lower amounts are ingested, feces return to a normal color.

Rapid Transit

Feces that travel through the digestive system faster than normal often come out green. The green color is attributed to the green color of bile. In normal digestion, the liver excretes bile to aid in the breakdown of fats. As the bile and feces travel through the intestines, enzymes change the color of the bile from green to brown. If feces travel through the digestive too rapidly, the enzymes do not get the opportunity to react with the bile and green feces is the result. Some of the causes of rapid bowel transit are allergies, Celiac disease, digestive upset, GERD, lactose intolerance and some bowel disorders. Occasional green feces is generally not a cause for concern and is most likely caused by digestive upset. If green feces is present often, a trip to a doctor is warranted.

Bowel Disorders

Bowel disorders that cause feces to travel through the digestive system rapidly sometimes result in green feces. Irritable bowel syndrome and ulcerative colitis are two examples of bowel disorders that cause rapid bowel transit.

The color of bile is altered by enzymes in the small intestine. If the small intestine has been surgically removed or if there is a condition that causes inflammation in the small intestine, green feces can result. Inflammation in the small intestine is often seen with Crohn's disease.

Infectious Gastroenteritis

Infectious bacteria and viruses cause rapid bowel transit, which leads to green feces. Common infectious culprits are giardia, salmonella and rotovirus (stomach flu).