Green stool most commonly appears after eating high amounts of green foods, but it can also occur because of antibiotics or other intestinal conditions, like irritable bowel syndrome and gut infections.

In newborns, the presence of dark green poop is generally normal, as it is usually meconium. This is the first stool that is formed in the newborn's intestine.

When green stools last more than 2 or 3 days, or if they are accompanied by other symptoms such as stomach pain, a swollen belly, vomiting or tiredness, it is important to consult a gastroenterologist to identify the underlying cause and begin the most appropriate treatment. Learn more about what your poop color means about your health.

What does green poop mean?

The main causes of green poop usually include:

1. Eating green food

Consuming green food like spinach, broccoli or lettuce, or eating food that contains green food coloring can lead to green poop. Stool that is green from diet can occur in both adults and children.

What to do: if you have green poop due to the intake of green food, the best thing to help the stool return to its normal is to avoiding eating the same food, at least for a while. The stool will usually go back to being brown once the green food has been excreted from the body, therefore, it is not a cause for a major concern.

2. Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a condition characterized by the inflammation of the intestinal villi, which typically causes stomach ache, flatulence and bloating, but can also lead to the production of green stools or yellow stools.

What to do: IBS symptoms can be managed by making some lifestyle changes, primarily diet changes and stress management. You are advised to adhere to an IBS diet as directed by a registered dietitian, and to carry out activities that reduce stress levels, which can stop symptoms from getting worse or progressing.

3. Intestinal infection

Intestinal infections caused by bacteria like salmonella or parasites like Giardia lambli can often cause green poop. This is because stool moves through the intestines much quicker in the presence of infections, which reduces the time that bile and other digestive enzymes have to breakdown the stool. This quicker movement can lead to green diarrhea.

Learn more about the symptoms specifically associated with parasitic infections in the intestine.

What to do: If you suspect you have an intestinal infection, the doctor will assess you and advise treatment as necessary. Treatment may involve the use of medication to treat the underlying microorganism causing the infection. Plenty of fluids and rest can also speed up recovery.

Check-out home remedies for intestinal infections that you can prepare to complement your doctor's prescribed treatment.

4. Use of antibiotics

Some medication, especially antibiotics, can significantly reduce the amount of flora present in the gastrointestinal tract, This can also has an effect with bile production. When bile comes in contact with specific flora and digestive enzymes, it becomes brown, which contributes to the brown color of stool.

When antibiotics are taken, the quantity of flora is affected, which causes the bile to remain green, resulting in green poop. Other medications, like iron supplements, may also interfere with bile and digestion and lead to green coloring.

What to do: Once your doctor has approved you to stop your medication, you should assess your poop color to see if it remains green. If it does, then you should inform your doctor, who may recommend probiotics.

5. Use of iron supplements

Using iron supplements can change the color of stool, making it appear darker than usual. This is a sign that the body is absorbing iron correctly. However, when the iron in oral supplements are not completely absorbed by the intestine, it can turn your poop dark green or black as a side effect.

Iron supplements are prescribed to prevent and/or treat iron deficiency anemia. It can also be used in some situations where the body needs higher concentrations of this mineral, which can occur in childhood or during pregnancy.

What to do: If you notice green stools after taking iron supplements, consult the prescribed to determine whether the treatment remains appropriate, or if another dose or form of supplementation (like IV iron) is required.

6. Bile

Bile is a substance that aids in the digestion process and helps to process fats. This liquid is stored in the gallbladder and produced by the liver.

When diarrhea is present and intestinal flow is faster than the body can absorb nutrients, it is possible that the bile released does not have time to be processed. This can lead to green poop.

What to do: You should consult a doctor if you have green diarrhea, as it may be a sign of a a bacterial or viral infection. The doctor will likely advise increased hydration and determine whether antibiotics are necessary to prevent complications

Learn more about what causes green diarrhea and what to do to treat it.

Green poop in babies

Meconium is the name given to a baby’s first stool, which is actually formed when the baby is still in the mother’s womb. Meconium is thick, viscous and green looking. This is because the gastrointestinal microbiota of the baby is still not completely developed and does not have the necessary bacteria to act on the bile. This makes the poop darker and gives it its green color.

It is normal for the baby to excrete meconium in the first 24 hours of being born. The color and consistency of the stool will progressively change in the following days due to the development of the gastrointestinal tract and consumption of breastmilk or artifical milk.

What to do: Meconium is normal in all babies, however, if the baby does not excrete any green poop after being born or if there are no changes in color within the first week of life, the baby should be assessed by the doctor.

Learn more about other colors your poop can have and what these changes can mean.

When to go to the doctor

You should seek medical attention when, in addition to having green stools, you also present symptoms such as:

Diarrhea;
Nausea or vomiting;
Loss of appetite;
Blood in the stool;
Headaches or dizziness.

Stool testing and additional exams may be ordered to determine the cause of the symptoms.