I take 400mg of folic acid in my multivitamin but i started taking a 400mg folic acid supplement as well and now i have black diarrhea is this normal?

Melena?: If you have black, tarry, malodorous stool please get checked promptly to ensure that you don't have GI bleeding. Peptobismol and iron are also possible causes for black stools.

Could be: Folic acid and iron pills may make your stool black. You can check the stool easily at your doctors office to be sure that it is not blood causing the darkness as well. best wishes.

No: Folic acid alone should not cause black stool,but if there is an iron supplement,then the iron would most likely be the cause. GI bleeding from the upper tract is another cause of black stool. The latter is easily detected by your physician with a simple test on a stool specimen.