Q: How does milk of magnesia work?

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Milk of magnesia is an over-the-counter laxative that is used for short-term constipation relief. This magnesium-based compound is a saline osmotic that draws water into the bowels and triggers bowel movements. Doctors advise against using milk of magnesia for long-term constipation relief because it can cause an imbalance in your body chemistry. 

Milk of magnesia ingredients:

  • Magnesium hydroxide

  • Sulfate

  • Citrate

  • Phosphate

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  1. Over-the-counter laxatives for constipation: Use with caution. Mayo Clinic.
  2. Don't bomb the bowel with laxatives. Harvard Health Publishing.