Your poop is a surprisingly useful health indicator. Changes in the texture, smell, and color of your stool can mean many different things. If your stool is suddenly greener than usual, you’re probably wondering if it’s time to see a healthcare provider. Below, doctors explain causes of green poop.
Meet the Experts: Anshika Khare, M.D., a gastroenterologist with Wellstar Health System; Wendi LeBrett, M.D., Los Angeles-based gastroenterologist; Haleh Pazwash, M.D., gastroenterologist at Gastroenterology Associates of New Jersey; Niket Sonpal, M.D., a gastroenterologist and adjunct assistant professor at Touro College of Osteopathic Medicine.
“Some common causes of green stool are usually dietary factors, such as green colored vegetables and/or artificially colored intake in food and beverages,” explains Anshika Khare, M.D., a gastroenterologist with Wellstar Health System. “Sometimes rapid transit of the gut can also lead to green stool because the bile that is present does not have enough time to get absorbed.”
The good news: In many cases, green poop isn’t cause for serious concern. In some cases, some tweaks to your diet should get things looking regular again. That said, if you’re experiencing other puzzling or unpleasant gastrointestinal symptoms or you suspect your diet isn’t to blame for the green hue, it’s best to see a doctor.
Causes of green poop
Eating green foods
This is the most common cause of green poop. “Green stool is usually the result of a high quantity of leafy, green vegetables in one’s diet,” says Niket Sonpal, M.D., a gastroenterologist and adjunct assistant professor at Touro College of Osteopathic Medicine. Common foods that can cause green poop with high intake include leafy greens (spinach, kale, chard), asparagus, matcha, pistachios, and anything containing green food coloring, says Wendi LeBrett, M.D., Los Angeles-based gastroenterologist.
Eating blue foods
Take a moment to think back to art class in elementary school where you learned about the color wheel. Blue + yellow = green. “By eating blue or purple berries, you can actually give yourself green stool, because blue tones mixed with yellow from the stomach’s bile can result in bright green,” says Dr. Sonpal. “This is usually the most surprising to my patients and tends to be the most fun to teach in the exam room.” Meanwhile, if your stool is bright red and you haven’t recently eaten foods like beets, Jello, or cranberries, get prompt medical attention as the red hue may be an indication of blood.
Gallbladder problems
In regular circumstances, bile is stored in your gallbladder. However, when that’s gone, your bile has nowhere to stay. So, when people who have their gallbladder removed, they may have loose green appearing stools, says Dr. LeBrett. “This is because excess bile can be secreted into digested food contents, which can cause more rapid transit in the gut.”
If you fall into this potential category, Dr. Sonpal advises you to “Be patient—it usually gets better on its own as your intestines get used to the increased volume of bile and adjust the absorption.” During recovery, pay attention to your body, stay in contact with your physician, and let them know if the coloring continues for more than eight to ten weeks.
Infection
An infection that affects your gut and triggers diarrhea can also cause green stool. “If you have an infection from bacteria like salmonella, E. coli, or C. diff; viruses; or parasites like giardia, it can bring on diarrhea and increased bowel movements,” says Dr. Sonpal. “This fast-moving stool doesn’t allow your naturally green bile to become brown.” If you notice this happening, Dr. Sonpal recommends seeing your doctor right away to identify the root of the problem.
Antibiotics
As if you didn’t have enough to worry about while you battle the aforementioned salmonella or C. diff, antibiotic treatments can also turn your stool green. “This is because antibiotics sometimes kill good bacteria along with the bad ones,” says Dr. Sonpal. “Without the good ones, we get occasional green stools from changes in the microbiome of our guts.” While on antibiotics, Dr. Sonpal suggests boosting your gut flora with probiotics—either through supplements or eating fermented foods like kombucha or kimchi.
Depo-Provera for birth control
“The Depo-Provera shot works to suppress ovulation and has been associated with bloating or weight gain in some women, but I have had some patients notice green poop most commonly after their first few doses,” says Dr. Sonpal. “We still don’t know why this happens, but it’s nothing to be concerned with and usually self-resolves. My personal belief is that it stimulates extra bile release, but we have no concrete proof yet.” Other medications can trigger different colorations. For instance, Pepto Bismol can temporarily turn stools black, as can iron supplements. If you don’t think your green stool is the result of your diet, schedule a visit with your doctor to address your concerns.
Other medications and supplements
Many medications can also trigger different colorations in your poop. Taking iron supplements can change the color of your poop to dark green (or black), says Haleh Pazwash, M.D., gastroenterologist at Gastroenterology Associates of New Jersey.
Other vitamins, supplements, and medications that can cause green poop include:
- Fiber supplements
- Supplements that contain chlorophyll, like wheatgrass, spirulina, barley grass, chlorella, and blue-green algae
- Medications that can cause diarrhea as a side effect, like metformin, Lexapro (escitalopram), Nyquil, Zoloft (sertraline), and indomethacin.
Why is poop normally brown?
The reason why poop is normally brown has to do with the combination of bilirubin and bile mixing with foods during the digestive process, says Dr. Pazwash.
Digestive contents in the gut initially appear green/yellow due to bile made by the liver and secreted by the gallbladder at the start of the small intestine, but this pigment turns brown as it travels through the gut into the colon before it is excreted as poop, says Dr. LeBrett. More specifically, stercobilin (a bile pigment) is responsible for the brown color of feces, says Dr. Pazwash.
When is colored poop cause for concern?
- Red poop may be due to bleeding in the latter half of the gut (usually the colon or the end of the small intestine), says Dr. LeBrett. If you haven’t recently beets, Jello, or cranberries, seek medical attention immediately.
- Black tarry poop may be a sign of bleeding in the upper part of the gut (stomach and first part of the small intestine) as blood becomes black as it travels through the gut, says Dr. LeBrett. “With young onset colon cancer on the rise, any concern for gastrointestinal bleeding should be evaluated by a doctor.”
- White poop may signal a blockage of bile flow and should also be evaluated, says Dr. LeBrett.
Red, black, and white poop should be evaluated by a doctor, especially if not associated with a particular food or medication, says Dr. LeBrett. “Sudden changes in poop color (green and yellow) with associated diarrhea that is persistent should also be evaluated.” Lastly, changes in poop color with sudden weight loss or significant abdominal pain should also be a sign to see your doctor promptly.
When to see a doctor for green poop
Poop with a greenish hue is not always cause for medical concern (especially if you’ve recently eaten a green or blue-colored birthday cake). Before seeing a doctor, if you are not experiencing any other signs of worry, you can try making changes in your diet to see if that helps your poop return to a healthy brown hue, suggests Dr. Pazwash.
However, if your green poop is associated with diarrhea and is an ongoing issue that has lasted several days, it should be evaluated by a doctor to rule out infection or inflammation, says Dr. LeBrett.
Read the full article here