Why is Your Poop Green & Stomach Hurts? 6 Causes.

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The most common cause of acute stomach pain and green poop is severe attacks of gastroenteritis (viral, bacterial, or protozoal). Moreover, chronic stomach pain and green stool may be due to any cause of chronic diarrhea such as infection, IBD, IBS-D, etc.

Green foods and food colorings may also play a role, but they don’t usually hurt your stomach.

The most common causes of stomach pain and green poop include:

  • An acute attack of stomach flu (viral gastroenteritis).
  • Other types of gastroenteritis and food poisoning such as bacterial and protozoa infections.
  • Overeating green leafy vegetables.
  • An attack of food intolerance.
  • An attack of IBS diarrhea.
  • Others include antibiotic-associated diarrhea, celiac disease, IBD, bile acid diarrhea, etc.

1 . Stomach flu (viral gastroenteritis).

Acute diarrhea is often due to an infection with a gut bug. The most common cause of digestive infection is viruses.

Acute viral gastroenteritis is the most common reason your stomach hurts and pooping green stool.

Causes of stomach flu.

Viruses account for up to 70% of all cases of acute gastroenteritis. Most of them are self-limiting and require supportive treatment only.


  • Acute onset of stomach cramps.
  • Acute onset of diarrhea. Often, the diarrhea is yellowish and watery. Then, it may become greenish due to the passage of unchanged bile in severe cases.
  • Nausea and/or vomiting.
  • Fatigue and body aches.
  • Fever may be present (often, of low grade).
  • Sings of dehydration may occur particularly in severe cases (when the poop is green): extreme thirst, dry mouth, peeing too little urine.
  • In severe cases of dehydration (especially in babies and the elderly): confusion, fainting, and coma may occur.

There is no specific organism that causes green poop. However, the green poop is a sign of severe diarrhea as the bile has not had enough time to be processed into its standard brown color.


The condition is often self-limiting. Therefore, only supportive treatment is needed. See a doctor if the stomach pain and green poop last for more than three days.

  • No medication targets stomach viruses (antibiotics are made for bacteria, not viruses).
  • However, viral gastroenteritis is usually self-limiting within a few days.
  • Good hydration with plenty of fluids to avoid dehydration (particularly with green poop).
  • Eat bland food such as the BRAT diet (bananas, Rice, Apple sauce, and Toast).
  • Avoid fatty, spicy, and fried food (They may cause hurt your stomach and increase nausea and vomiting).
  • Probiotics may help reduce the condition and regain the normal beneficial bacteria inside your gut.
  • Over-the-counter antidiarrhea (such as Pepto Bismol and Immodium) may help to reduce the severity of diarrhea.
  • Over-The-Counter antispasmodics may decrease stomach cramps.

2. Other types of gastroenteritis and food poisoning.

Viruses are the commonest cause of acute gastroenteritis. However, Other organisms also cause gut infections with significant diarrhea, stomach pain, and green poop.

The different organisms that cause gastroenteritis are in the table below (reference):

Viral: 50%–70%Bacterial: 15%–20%Parasitic: 10%–15%
Enteric adenovirus types 40 and 41CampylobacterCryptosporidium
AstrovirusE ColiIsospora
Some picornavirusesYersiniaMicrosporidium
 C difficile

Bacterial and protozoal gastroenteritis can cause more severe digestive system infections such as foodborne illnesses and dysentery.

The following are definitions of the different varieties of gastroenteritis:

  • Bacterial gastroenteritis: acute gastroenteritis caused by bacterial infection. They are generally more severe than viral gastroenteritis and may cause high-grade fever.
  • Food poisoning (foodborne illness): refers to any disease caused by ingesting food contaminated with infectious organisms or toxins. Food poisoning symptoms are often in severe acute gastroenteritis with vomiting and diarrhea.
  • Dysentery is another specific form of gastroenteritis where the inflammation is predominantly in the colon and the rectum. Dysentery is a severe form of diarrhea with intense urgency (Tenesmus) and passage of mucus and blood with poop.

The symptoms of other types of gastroenteritis are essentially the same (stomach cramps, nausea, vomiting, diarrhea, yellowish or green poop).

Bacterial gastroenteritis is often more severe, with high-grade fever. Dysentery causes severe tenesmus with the passage of mucus or blood with the poop.

All types of severe gastroenteritis can cause green poop and stomach pain. Diarrhea causes the rapid passage of bile through the digestive tract. Unchanged bile appears as watery green poop.

Green watery diarrhea is a sign of severity. Call your doctor if the diarrhea is severe, high-grade fever, or has signs of dehydration.

3. Eating Excess Green vegetables.

The most common cause of green poop is green foods such as green leafy vegetables. In healthy people, eating green leafy vegetables doesn’t hurt the stomach.

However, Some of these foods may cause digestive issues such as gas and stomach pain when you eat them in excess.

Most green leafy vegetables that cause green poop are high FODMAP foods.

FODMAP refers to Fermentable Oligo, Di, Monosaccharides, AND Polyols. Unfortunately, too many people are intolerant to FODMAP foods, especially those with irritable bowel syndrome.

Common high FODMAP vegetables include:

  • Artichoke (globe, Jerusalem, and pickled)
  • Asparagus
  • Beetroot
  • Bitter Melon
  • Black Garlic
  • Broccoli (stalks only)
  • Broccolini (whole)
  • Brussel sprouts
  • Butternut squash
  • Babbage, savoy
  • cauliflower
  • Celery
  • Chilli (ancho, chipotle)
  • Corn kernels, canned
  • Galic
  • Indian gooseberry
  • Karela
  • Kimchi
  • Leek (bulb)
  • Lotus root (dried)
  • Mangetout
  • Mushroom (button, enoki, porcini, portobello, shiitake, and black chanterelle)
  • Onions (Spanish, white, spring, and pickled onions)
  • Peas
  • Pumpkin (butternut)
  • White cabbage, sauerkraut
  • Yucca root

Also, food colorings such as green ice pops and colored mixes may trigger stomach pain and cause green poop at the same time (reference).

Review the types of food you ate before the onset of stomach pain and green poop. For example, eating green leafy vegetables that are high in FODMAP can be the cause of your green poop and stomach pain.

The condition is often short-living for a few days and is preventable by avoiding or decreasing the consumption of such foods.

Keep a food diary to record the foods and associated symptoms. It may help your figure out the cause of green poop.

4. An attack of food intolerance.

Food intolerance is a difficulty digesting certain types of food, leading to their accumulation inside the digestive tract. The accumulation of maldigested foods leads to diarrhea, bloating, and nausea.

Food intolerance affects one in every five persons worldwide. The most common type of food intolerance is lactose intolerance found in milk and dairy products.

Common types of food intolerance:

1- Lactose intolerance (intolerance to milk and other dairy products.

2- Caffeine intolerance (in coffee, chocolate, etc.).

3- FODMAP intolerance (a group of short-chain carbohydrates that ferment rapidly inside your intestine and may cause random diarrhea). Most people with irritable bowel syndrome are intolerant to FODMAPs.

4- Fructose intolerance (present mainly in honey and fruits).

5- Gluten intolerance (celiac disease).

6- Other types of food intolerance such as aIcohoI intolerance, amines, sulfites, eggs, etc.

Symptoms suggestive of food intolerance:

  • Recurrent attacks of diarrhea come and go every time you eat excess amounts of the offending food.
  • The diarrhea is often yellowish. However, if the attack of diarrhea is severe, poop may turn green.
  • Stomach pain.
  • Bloating and distension.
  • Gas and flatulence (farting too much).
  • Rarely it can cause constipation.
  • Nausea with or without vomiting may also occur randomly.
  • The symptoms start shortly after eating and may last for days.

5. An attack of IBS-Diarrhea.

Many people are another widespread condition that causes recurrent stomach pain and bowel changes.

Research estimates that up to 40% of IBS sufferers don’t know they have it. This is because the symptoms are usually moderate and non-specific.

Sporadic attacks of diarrhea and stomach pain may suggest that you have IBS. The main feature of IBS is recurrent stomach pain. The diarrhea-predominant IBS may present with green poop when the attack is severe.

Irritable bowel syndrome is linked to the intolerance to FODMAPs (explained before).

How to suspect IBS (symptoms):

  • Stomach (abdominal) pain that is recurrent at least one day per week (for several months).
  • The pain improves or worsens after you poop.
  • The pain is associated with a change in stool form (becoming more loose or hard).
  • The pain is associated with a change in stool frequency (diarrhea or constipation).
  • In severe attacks of IBS-diarrhea, Poop may turn green as bile will not have enough time inside the digestive tract to turn brown.
  • All the symptoms come and go intermittently in attacks.
  • Triggers are usually food and psychological stress.
  • Random diarrhea with mucus is frequent with IBS.

6. Others

The causes of green poop and stomach pain are far more complex than the five common causes explained above.

The below conditions are less common causes of such conditions.

If you have severe unexplained symptoms with green poop, it is better to consult your doctor.

  • Recent gallbladder removal (post-cholecystectomy diarrhea).
  • Antibiotic-associated diarrhea.
  • Other medications that can cause severe diarrhea include metformin, laxative abuse, GERD and peptic ulcer medications, immunosuppressive drugs, chemotherapy, etc.
  • Bile acid diarrhea.
  • Celiac disease.
  • Inflammatory bowel diseases such as Crohn’s disease and Ulcerative Colitits.
  • Acute hepatitis A infection.
  • Endocrinal diseases causing severe diarrhea such as hyperthyroidism, Addison’s
  • Colorectal cancer.
  • Neuroendocrine tumors such as

When to see a doctor for green poop and stomach pain:

  • Stomach pain and green poop are associated with severe diarrhea (especially in babies)
  • Prolonged periods of green poop or stomach pain for more than days without apparent cause.
  • Weight loss.
  • Nausea or vomiting.
  • Sings of dehydration include extreme thirst, peeing little urine, dark urine, confusion, or coma.
  • Fever.
  • Presence of blood in the stool.