Why is my poop green? What does this mean?

Medically reviewed by Carmen Pope, BPharm. Last updated on Aug 29, 2024.

Official Answer by Drugs.com

It is not uncommon for poop to change color. The two main causes of poop color change are diet and conditions that change how fast food travels through our intestine.

Dietary causes of loose green poop may include:

Broccoli, green leafy vegetables, kale, spinach, wheatgrass
Iron supplements
Licorice
Green or black food coloring.

Conditions that could cause loose green stools include those that change how fast food travels through the intestine because bile (a yellow-green fluid that digests fats) doesn’t have time to break down.

Bile is produced by our liver and stored and released in our gallbladder. Anytime we eat food that contains fat, even a small amount of fat, a signal is sent to our gallbladder to release bile, which flows into the upper part of our small intestine through two small tubes (the cystic duct and common bile duct). Bile digests fats and also eliminates old red blood cells and some toxins from our bodies.

As bile travels down our intestine it is chemically altered by enzymes, and the color changes from green to brown. However, this process takes time. Conditions that can quicken intestinal transit time, meaning that bile retains some of its yellowish-green color, include:

Infection from bacteria, viruses, or parasites (eg, E. coli, Giardia, norovirus, salmonella)
Crohn’s disease
Gall bladder disease
Irritable bowel syndrome
Some medications, including Depo-Provera (medroxyprogesterone birth control shot), indomethacin, and iron supplements, have reported green poop as a side effect
Ulcerative colitis.

Generally, a color change accompanied by other symptoms, such as abdominal pain, diarrhea, cramps, weight loss, or fever should be investigated further.

Yellow poop changes may be a sign of infection, poor absorption, liver and gall bladder disease, celiac disease, pancreatic disorders, or dietary reasons. Bright red or black poop may indicate the presence of blood and you should seek medical advice straight away.

For more information see Green stool.

Should you take probiotics with antibiotics?

There is controversy about whether you should routinely take probiotics with antibiotics and the question cannot be answered with a straight yes or no. Evidence for taking probiotics with antibiotics includes a Cochrane review which reported that children who were given a course of probiotics after antibiotics had less diarrhea. Evidence against taking probiotics with antibiotics includes a 2019 Italian study that reported that the gut microbiome of people given probiotics after antibiotics took six months to return to its normal state compared to only three weeks for those not given any probiotics. More studies are needed before a definite statement can be made. Continue reading

What to eat when you have a stomach virus?

When you have a stomach virus, it is best to eat bland and easy to-digest foods until your symptoms improve, such as:

soda crackers (“saltines”)
plain toast
gelatin (“jello”)
bananas
rice
plain chicken

It’s best to stay away from caffeine, dairy, alcohol, high amounts of sugar, and fried or spicy foods until you feel better. Continue reading

Why does metformin cause diarrhea?

According to the manufacturer, about 53% of people taking metformin immediate-release tablets experienced diarrhea in one clinical study. In another study, 10% of people taking metformin extended-release tablets reported diarrhea as a side effect. Continue reading

Why is my poop green? What does this mean?

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