What Causes Green Diarrhea and What to Do About It

Passing one solid, green stool is nothing to be concerned about. Even green diarrhea may be within the range of normal stool. Usually, foods like leafy vegetables, supplements, and medications are to blame.

However, you could also have green diarrhea from a medical condition such as a stomach infection or digestive problem.

This article goes over the different causes of green diarrhea, what to do about it, and when you should talk to your healthcare provider.

Why Green Diarrhea Happens

causes of green diarrhea
Verywell / Joshua Seong

In a broad sense, green stools are caused by two things:

  • Something you consumed that added color to your stool
  • Something abnormal in the digestive process, usually involving bile, a green substance that helps digest fat in your small intestine

Foods, drinks, medications, and medical conditions are all possible culprits.

Foods That Cause Green Poop Medications That Cause Green Poop Conditions That Cause Green Poop
Green, leafy veggies (like kale) Antibiotics Food intolerance/ sensitivity
Purple or blue foods, (like grapes) Anti-diarrheals Infections, including food poisoning
Foods made with green, purple, or blue dyes (like popsicles) Depo-Provera Inflammatory bowel disease (IBD)
Coffee Iron supplements Inflammatory bowel syndrome (IBS)
Spicy foods Laxatives Non-alcoholic fatty liver disease
Alcohol Premenstrual syndrome

If you consume a food or drink that turns your poop green, it is because whatever you consumed either had a green or similar hue, or it had a laxative effect on the body. Sped-up digestion is also at play in cases where a medication or medical condition is the root cause.

As stool continues through the digestive tract, the bile becomes dark brown. If the stool is still green by the time it comes out, it could mean that it went through the large intestine too fast to be turned brown. This is known as "rapid transit" or "decreased colonic transit time."

This is especially true with green diarrhea rather than a fully-formed stool.

Food and Green Diarrhea

If you experience green diarrhea, or solid stools that are green, think about what you've eaten over the past several days. Even if the food wasn't actually green, it could be the cause.

Colored Foods and Drinks

Foods that can cause green stool include:

  • Large amounts of green leafy vegetables, due to chlorophyll (a green pigment in plants)
  • Purple or blue foods (in blueberries, grapes, grape or berry juice, red wine)
  • Green, purple, or blue dyes (in candy, popsicles, soda, gelatin, snowcones, slushies, etc.)

Delayed Color Change

A green stool might not appear for a day or two after eating foods that turn poop green. By then, it is easy to forget what you've eaten. If you think food caused your green stool, just give it a little time. The color should go back to normal in a day or two.

One of the biggest times to see green stools is during holidays when green food dye is commonly used, such as Christmas, Easter, and St. Patrick's Day.

Foods With a Laxative Effect

Some foods with a laxative effect speed up digestion. They can contribute to both green stools, especially if you eat a lot.

These foods not spending a long enough time in the large intestine also means that less water is absorbed, resulting in loose stool.

Foods with a laxative effect that can cause green diarrhea include:

  • Coffee
  • Spicy foods (jalapeños, chili peppers)
  • Alcohol

Green diarrhea or stools from laxative foods is often dark green.

Medications and Supplements

The different medications and supplements that can give you green diarrhea or stools do so for a variety of reasons.

  • Iron supplements often make stool dark green that may look black when in solid stools.
  • Laxatives make digestion faster, which leads to green diarrhea due to green bile and higher water content.
  • Antibiotics alter gut bacteria, which can lead to more bile in stools and diarrhea.
  • Anti-diarrheal medications: Pepto-Bismol/Kaopectate (bismuth subsalicylate) can turn stools green or black due to its interaction with digestive enzymes.
  • Depo-Provera contraceptive: This shot may cause green stools, diarrhea, and many other digestive side effects because of its potential effects on the adrenal glands, which produce hormones that help regulate several body functions.

Under most circumstances, these causes of green diarrhea or stools are nothing to worry about.

Still, if your stools change color or consistency soon after starting a new medication or supplement, check with your healthcare provider or pharmacist to see whether it's a normal side effect.

Also note that stools that are black and tarry stools, as opposed to dark green/blackish, may be a sign of gastrointestinal bleeding. If you experience this, report it to your healthcare provider immediately.

Medical Conditions

The several medical conditions that can cause green diarrhea do so because of their effect on bile and transit time.

Food Poisoning and Infection

If you suspect food poisoning or a gastrointestinal infection and it doesn't get better quickly or symptoms are severe, you should see a healthcare provider. Symptoms to watch for include:

  • Bloody diarrhea
  • Diarrhea lasting longer than three days
  • Oral (mouth) temperature above 102 degrees Fahrenheit
  • Frequent vomiting
  • Signs of dehydration (lack of urination, dry mouth and throat, dizziness)

Unless you have concerning symptoms, you probably don't need medical treatment. The key is to get a lot of fluids and electrolytes so you don't get dehydrated from diarrhea and vomiting. Over-the-counter (OTC) anti-diarrhea medications can help as well.

For more severe cases, healthcare providers may prescribe antibiotics.

Food Intolerance or Sensitivity

Common food issues include:

  • Celiac disease
  • Non-celiac gluten sensitivity
  • Lactose intolerance
  • Fructose intolerance
  • Sensitivities to ingredients such as monosodium glutamate, caffeine, artificial sweeteners, food additives and preservatives

The most common treatment for food intolerance or sensitivity is eliminating problem foods from your diet. If you're not sure what's causing your symptoms, you may need your healthcare provider to run some diagnostic tests.

Premenstrual Syndrome (PMS)

PMS is a set of physical and mood symptoms you experience just before a menstrual period. Not everyone with PMS gets green diarrhea, but it's a possible symptom. Other symptoms may include:

  • Moodiness/irritability
  • Insomnia
  • Breast tenderness
  • Bloating, cramping, and weight gain
  • Headache
  • Fatigue
  • Digestive problems

Exercise, less salt and caffeine, and not smoking or drinking alcohol is often helpful with PMS. For symptoms that interfere with your daily life, your healthcare provider may prescribe:

  • Hormonal contraceptives ("the pill," implants, or shots) or other hormonal treatments
  • SSRI antidepressants (selective serotonin reuptake inhibitors) such as Lexapro (escitalopram), Zoloft (sertraline), Prozac (fluoxetine)
  • Non-steroidal anti-inflammatory drugs (NSAIDs) like Advil (ibuprofen) or Aleve (naproxen)

Inflammatory Bowel Disease

Inflammatory bowel disease is an umbrella term for ulcerative colitis and Crohn's disease, which are serious conditions that affect your digestive system. Common symptoms include:

  • Persistent diarrhea
  • Abdominal pain
  • Rectal bleeding and bloody stools
  • Unintended weight loss
  • Fatigue

Common treatments include:

  • Anti-inflammatory drugs called 5-aminosalicylic acid (5-ASA), such as Salazopyrin (sulphasalazine), Mezavant (mesalazine), Dipentum (olsalazine)
  • Immunomodulators such as methotrexate, Imuran (azathioprine), Purinethol (6-mercaptopurine)
  • Corticosteroids like prednisone and Entocort (budesonide)
  • Biologic drugs like Humira (adalimumab), Cimzia (certolizumab), Remicade (infliximab)

Irritable Bowel Syndrome (IBS)

IBS causes a range of digestive problems in addition to green stools. Common symptoms include:

  • Diarrhea (green or otherwise), sometimes alternating with bouts of constipation
  • Bloating
  • Abdominal pain
  • Whitish mucus in the stool

Diarrhea-predominant IBS treatments may include:

  • Eating more fiber and less gluten
  • Special eating plans such as the low-FODMAP diet
  • Increasing physical activity and sleep
  • Lowering stress levels
  • Medications such as loperamide, Xifaxan (rifaximin), Viberzi (eluxodoline), Lotronex (alosetron)

Non-Alcoholic Fatty Liver Disease (NAFLD)

NAFLD generally has no symptoms. Sometimes, it may cause:

  • Green diarrhea
  • Fatigue
  • Upper-right-side abdominal pain

More advanced cases may cause:

  • Loss of appetite
  • Unintended weight loss
  • Weakness
  • Fluid retention
  • Bleeding

Treatment for this condition includes:

  • Gradual weight loss (for those with overweightness or obesity), as rapid weight loss can worsen liver disease
  • Lowering cholesterol and triglyceride levels
  • Avoiding alcohol
  • For type 2 diabetics, controlling blood glucose levels

Researchers are looking into possible medicines for NAFLD but none are available so far.

Green Stools in Infants, Toddlers, and Kids

Green stool is a normal occurrence in breastfed infants, especially in the first days after delivery, and is no cause for alarm.

In infants, stools will gradually change to yellow and brown as the baby approaches their first birthday and more varied foods are added to the diet.

For formula-fed babies, green stool may continue for several months. This is likely due to the iron content of some formulas.

In addition, giving an infant or a child an iron supplement (as is commonly recommended by pediatricians) may also cause green stools.

Some parents say their children have green stools while teething. There is no scientific evidence to support this common observation, however.

In older children, green stool could be food-related or due to eating non-food items, such as crayons.

If your child has swallowed or eaten a non-food object, call Poison Control at 1-800-222-1222.

When to Call a Healthcare Provider

In some situations, green diarrhea can be a sign of a more serious problem. You should call your healthcare provider if green (or other) diarrhea:

  • Continues for more than three days
  • Is accompanied by severe pain and stomach cramps
  • Is accompanied by vomiting for more than 24 hours
  • Occurs along with signs of dehydration, such as dry skin, mouth, and lips, and decreased urine output
  • Occurs alongside other changes in your bowel habits

Summary

Green diarrhea or stool is unusual but not typically something to worry about. 

The most common cause of green stool is diet. Eating green, blue, or purple foods is often the culprit—especially when they contain food dyes. 

Several medical conditions can cause green diarrhea. Many of them involve rapid digestion, which makes bile retain its green color instead of turning brown. Green diarrhea on its own that lasts for more than a few days or comes and goes could be a sign of a digestive issue. 

Call your healthare provider if diarrhea lasts longer than three days or is accompanied by vomiting for more than 24 hours. 

Frequently Asked Questions

  • Why do I have green poop and pain in my stomach?

    Green poop plus stomach pain may be due to certain medications or a medical conditions, such as food poisoning, a food sensitivity, or inflammatory bowel disease.

  • Why would I have green poop during pregnancy?

    Green poop is somewhat common in the earliest weeks of pregnancy, during the third trimester when digestion speeds up, and if you take iron supplements or prenatal vitamins. It can also be due to food, especially if you've increased your consumption of green or purple vegetables.

  • Can COVID-19 cause green poop?

    Yes, it can. COVID-19 can impair the way fat is broken down in your digestive system. Fatty stools may look yellow or, if there's a high bile content (which is common), green.

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By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.