Can Magnesium cause black stools? 

Can Magnesium cause black stools? 

No, Magnesium does not darken the color of stools or make them appear black. Magnesium supplements are frequently used and this is not considered a common side effect of them. 

Too much intake of dietary sources of Magnesium – like leafy green vegetables – may make your stools appear a little greener. However, black-coloured stools should not be caused by Magnesium – either dietary or in the form of supplements. 

What to do if you’re having black stools while taking Magnesium supplements? 

If the colour of your stools appears to be black while taking Magnesium, immediately reach out to your healthcare provider. A little dark-colored stool is considered normal and the food we eat can also affect that. 

Some people are constipated and they may notice their stools to be slightly darker than usual. Magnesium is not commonly associated with constipation, but people taking too much of it may experience constipation. However, none of this explains black stools. 

Why black stools should not be ignored?

Tarry-black stools could be a sign of gastrointestinal bleeding and it should be immediately checked (1). Your doctor may ask for your stool sample for a fecal occult blood test which detects the presence of blood in your stools (2). 

This will help determine whether or not you have gastrointestinal bleeding. If you do, your doctor will begin the treatment right away to stop GI bleeding. This is why it is important to report to your doctor right away.

References

  1. National Library of Medicine (US). Gastrointestinal Bleeding [Internet]. Bethesda (MD): National Institutes of Health; 2019. Available from: https://medlineplus.gov/gastrointestinalbleeding.html
  2. Fecal occult blood test [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2004. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279209/

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References

1.-

National Library of Medicine (US). Gastrointestinal Bleeding [Internet]. Bethesda (MD): National Institutes of Health; 2019. Available from: https://medlineplus.gov/gastrointestinalbleeding.html

2.-

Fecal occult blood test [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2004. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279209/