Changes in stool color happen from time to time. Though not always cause for concern, a persistent change in your stool color can be an important indicator of your overall health.
In many cases, green-colored stools are caused by a change in your diet, especially if you’ve eaten a large amount of green leafy vegetables.
But there are other possible causes of green-colored stools, some of which may warrant medical attention. Understanding the different possible causes of green-colored stool can help you determine whether or not to seek advice or treatment from a medical professional.
What Does Green Stool Mean?
Stool color can be an important indicator of your bowel and overall health. Green stool can indicate a variety of possible causes, including a change in diet, an infection, or certain medications.
Symptoms and Causes
There are several possible causes of green-colored stool, some of which can cause additional symptoms. Understanding the signs of each possible cause can help you decide whether or not to seek help from your medical provider.
In most cases, green-colored stools are caused by the consumption of certain foods. Specifically, high consumption of green leafy vegetables or foods containing green food coloring can turn stools green.
These can include:
- Honeydew melon
- Green apples
- Blueberries, or other purple fruits or vegetables
Changes in stool color caused by certain foods in your diet are usually temporary.
However, if your green-colored stool persists for several days, reach out to your provider for more information.
Green stools can also indicate that your food is moving through the large intestine too quickly, sometimes as a result of an infection.
The following parasitic, viral, and bacterial infections can cause green-colored stools:
- Giardia: The tiny parasite giardia can be found in soil, food, or water that has been contaminated with feces from infected people or animals. Short-term symptoms include diarrhea, gas, stomach cramps, upset stomach, nausea, vomiting, and dehydration. The infection can also cause foul-smelling and floating stools, as well as green-colored stools.
- Salmonella or E. coli: A bacterial infection of salmonella or E. coli can also cause green-colored stools. With E. coli, most people will start to feel symptoms three to four days after eating or drinking something that contains the bacteria. But with salmonella, symptoms can take as little as six hours or as long as six days to appear after eating the contaminated food or drink. Symptoms of these bacterial infections can include severe stomach cramps, diarrhea (often bloody), and vomiting.
- Norovirus: This highly contagious virus can cause vomiting and diarrhea as well as green-colored stools and is spread easily between people.
If you think you may have an infection, it’s important to reach out to your medical provider to determine whether additional treatments may be necessary.
Though rare, digestive problems that affect your absorption of bile can also result in green-colored stools. Short-term diarrhea, irritable bowel syndrome (IBS), and the recent removal of your gallbladder can affect your body’s ability to break down bile, resulting in green-colored stools.
Antibiotics or medication
There are some medications and supplements that can temporarily cause green stools.
These medications and supplements include:
- Antibiotics: Antibiotics can be prescribed to kill harmful bacteria in the body, but they can also destroy the beneficial bacteria that work to maintain a healthy balance in the gut. While taking antibiotics, you may notice a temporary green tint on your stools due to the bacteria destruction.
- Iron supplements: Iron supplements are often used as a treatment for anemia. Side effects of the medication include constipation, nausea, vomiting, and black or green-colored stools.
Anal fissures can be caused by straining during bowel movements, often brought on by constipation.
However, they can also develop as a result of chronic diarrhea or inflammatory bowel disease (IBD). In those cases, you may also experience green-colored stools.
Can Green Poop be Cancerous?
Green stools are rarely a sign of cancer.
Changes in stool color caused by cancerous tumors are often black, tarry, or bright red in color. However, if you’re experiencing distressing symptoms along with your green stool, like fever, diarrhea, or vomiting, reach out to your healthcare provider as soon as possible.
Green Stool Consistency
Changes in stool consistency can happen alongside changes in stool color.
For example, some people may experience greenish stools that are loose, watery, mucousy or floating. It’s important to note any changes in consistency when speaking to your provider to help determine the cause of these changes.
Other Poop Colors
Healthy stools are often brown in color, well-formed, and easily passed. However, a day or two of irregular stool color isn’t usually a cause for concern. Stools can temporarily change color for a variety of reasons.
Here are some examples of what the different colored stools can indicate:
- Pale or clay-colored: Pale or clay-colored stools can be an indication of a bile duct obstruction, which can be caused by certain medications, like antidiarrheal drugs (drugs for relieving diarrhea).
- Yellow: Yellow stools are usually a result of excess fat in stools, which can have several causes, including malabsorption, celiac disease, and other medical conditions.
- Black: Black stools can signal a variety of conditions, including bleeding in the upper intestinal tract. But black stools can also happen when taking iron supplements or eating an excessive amount of black licorice.
- Bright red: Bright red stools can be caused by eating certain foods, like beets, cranberries, tomatoes, or red gelatin. In other cases, it can be a sign of bleeding in the lower intestinal tract.
When to See a Medical Provider
Temporary green stools are rarely a cause for concern.
Unless you’re experiencing additional symptoms, you can continue monitoring your stools for a few days to see if they return to their normal color.
But if you’re experiencing green-colored stool that won’t go away or bothersome symptoms like abdominal pain, weight loss, blood in stool, fever, or vomiting, reach out to your provider for help.
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Frequently Asked Questions
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.
K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.
Anal Fissures. (n.d.).
E. coli (Escherichia coli). (2021).
End Results: What color is your poop and other pressing fecal matters. (2018).
Taking iron supplements. (2021).