Why does stool turn black after taking iron supplements?
Disease description:
I was diagnosed with iron deficiency and have been taking iron supplements recently; however, my stools have turned black. Could you please explain why iron supplements cause black stools?
Doctor's answer (2)
Dr. Lu Chaohui
Typically, the iron in iron supplements reacts with hydrogen sulfide in the gastrointestinal tract to form black ferrous sulfide, resulting in black stools. While taking this medication, patients should avoid spicy and irritating foods and must abstain from smoking and alcohol consumption. If black stools occur after taking iron supplements and are accompanied by other systemic symptoms or discomfort, the medication must be discontinued immediately, and the patient should seek medical evaluation and treatment at a hospital to prevent potential adverse effects or complications associated with continued use.
