Changes in stool color often have harmless causes. However, it's crucial to know when a change in stool color may indicate something more serious. The foods you eat and even the vitamins and supplements you take can influence the color of your stool. Talk to your doctor if you have concerns.
Iron is perhaps the most commonly known supplement that changes stool color. If you've recently started taking an iron supplement or a multivitamin that contains iron, you may notice that you have darker stools. Iron can make your stools very dark, or even black, and this is a normal side effect. It's actually a good sign that the iron tablets are working as intended, says MedlinePlus.
Whole Food Supplements
Some vitamin supplements are made from whole foods such as vegetables and fruit and serve as a concentrated source of nutrients. Theoretically, taking a whole food supplement may cause stool discoloration. Plants only contain several brightly colored nutrents like chlorophyll -- a green pigment -- that contribute to their color. Taking a whole food supplement, or a vitamin that contains chlorophyll, may cause your stool to take on a greenish color because of the amount of chlorophyll you're taking in.
Supplements With Carotenoids
Carotenoids are a group of plant pigments responsible for the yellow, orange and green pigments in plants. Taking a multivitamin high in beta carotene or any of the other carotenoids can potentially change the color of your stool. Green or dark stools can be a side effect of a prenatal vitamin that contains beta carotene, according to Drugs.com.
Diet and Stool
If you've recently changed your diet or started eating new foods, you may notice a change to your stool color. For example, if you've eaten beets within the last couple of days, your stool may take on a purplish-red color. In some cases, stool discoloration can indicate health issues such as hepatitis, hemorrhoids or gallstone disease. It's always best to discuss your concerns with your doctor.