Can Vitamins Change the Color of Your Bowel Movements?

Can Vitamins Change the Color of Your Bowel Movements?

Can Vitamins Change the Color of Your Bowel Movements?
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Updated on August 6, 2025
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It can be alarming when you go to the toilet for your daily business and notice that the color of your stool has changed. If you’ve introduced a new vitamin, mineral, or other type of supplement into your daily regimen, that might be the cause. Taking a new supplement is one of the most common reasons for a change in the appearance of your stool.

However, changes in stool color may also indicate a serious health problem, so if things don’t go back to normal a few days after stopping the supplement, be sure to tell your doctor.

Iron

Iron supplements are taken to build red blood cell counts in people who have anemia. They’re also often recommended to women to compensate for blood loss experienced during menstrual periods.

Whether taken as a tablet or in liquid form, iron supplements can cause someone to have darker than normal, dark green, or even black stool. If you take an iron supplement or a multivitamin that contains iron, you should know that darkened stool is a common side effect.

If the dark stool also has a foul smell and is accompanied by other symptoms like abdominal pain, lightheadedness, or vomiting, it’s important to let your doctor know, as these may be signs of a more serious issue.

Chlorophyll

Chlorophyll is believed to have numerous health benefits, from fighting acne to aiding wound healing to helping prevent cancer.

 While there’s little research to support these claims, chlorophyll is safe for human consumption.
You can get your chlorophyll in a shot of wheatgrass juice, which has a medicinal, organic taste. But don’t be surprised if your stool appears green afterward.

Carotenoids

Vegetables such as bell peppers, carrots, tomatoes, and pumpkins get their vibrant colors from a group of pigments called carotenoids.

 Taking multivitamins or supplements with high levels of carotenoids — beta-carotene is a common one — may cause your poo to turn yellow, orange, or other colors of the rainbow.

Other Whole-Food Supplements

There are many nutritional whole-food supplements made from plant matter. Turmeric (and its active ingredient curcumin), licorice root, and antioxidants in the form of red wine flavonoids are just a few of the various types of ground-up plant matter that you can swallow in pill form.

But if you’re ingesting large quantities of these products, it’s quite possible that you could wind up changing the color of your stool.

Antacids

Bismuth subsalicylate is an ingredient used in certain medications for acid indigestion or diarrhea. Found in Pepto-Bismol, Kaopectate, and similar over-the-counter products, it can cause dark or black stool, just as iron supplements do.

The Takeaway

  • Introducing certain vitamins and supplements — such as iron, chlorophyll, and carotenoids — into your diet can lead to changes in stool color.
  • This change in stool color is harmless, and your bowel movements should return to normal once the supplement is reduced or removed from your diet.
  • Changes in stool color that persist after stopping the supplement may require medical evaluation, so be sure to tell your doctor if that’s the case. And it’s always a good idea to check in with your medical provider before starting a new supplement.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
Resources
  1. Can Food Change the Color of Your Poop? Cleveland Clinic. February 26, 2025.
  2. Iron Deficiency Is a Huge Problem for Girls. Columbia University Irving Medical Center. January 24, 2024.
  3. Taking Iron Supplements. MedlinePlus. July 8, 2023.
  4. Bloody or Tarry Stools. Mount Sinai.
  5. Higdon J et al. Chlorophyll and Metallo-Chlorophyll Derivatives. Oregon State University. March 2022.
  6. Alexander H. 6 Things to Know About Chlorophyll. MD Anderson Cancer Center. April 21, 2021.
  7. Why Is Your Poop Green? Cleveland Clinic. January 9, 2025.
  8. Eat the Rainbow: The Health Benefits of Carotenoids. Cleveland Clinic. July 12, 2023.
  9. 4 Things That Cause Yellow Diarrhea. Cleveland Clinic. March 5, 2025.
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Simran Malhotra, MD

Medical Reviewer
Member of American College of Lifestyle Medicine
Simran Malhotra, MD, DipABLM, CHWC, is a triple board-certified physician in internal medicine, hospice and palliative care, and lifestyle medicine, as well as a certified health and wellness coach. She is currently practicing part time as an inpatient palliative care physician at Medstar Health after serving as the palliative care medical director at Franklin Square Medical Center in Baltimore for a little over four years.

Dr. Malhotra completed her internal medicine residency at Medstar Franklin Square Medical Center, where she also served as chief resident in 2015. She completed her fellowship in hospice and palliative medicine at Johns Hopkins Hospital in 2016. She was named Top Doc in Palliative Medicine in 2019 and 2020 by Baltimore Magazine.

On a personal note, she is a BRCA1 previvor with a strong family history of breast and female reproductive cancers, and underwent a risk-reducing bilateral mastectomy and total hysterectomy in 2020 at 32 years old. After learning about her own genetic risk of cancer, and grounded in her professional experiences in palliative care, she founded Wellness By LifestyleMD, a platform where she works with and educates women at high risk for cancer with or without genetic mutations on the powerful impact that positive lifestyle changes can have on their quality of life and even longevity.

In addition to being a diplomate of the American College of Lifestyle Medicine, she completed the T. Colin Campbell plant-based nutrition certification in 2019, the CHEF culinary coaching certification in 2020, and the WellCoaches health and wellness coaching certification in 2022. She is a member of the ACLM women’s health member interest group and serves as the co-chair of the breast cancer subcommittee.

Malhotra has been featured on several blogs and podcasts, where she has shared her unique perspectives and experiences from palliative care as well as from being a genetic mutation carrier who is passionate about using lifestyle as medicine.
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Martin Booe

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Martin Booe is a health, fitness and wellness writer who lives in Los Angeles. He is currently collaborating on a book about digital addiction to be published in the UK this December.

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