Which condition is Milk of Magnesia primarily used for?

Milk of Magnesia is primarily used for treating constipation. This over-the-counter medication contains magnesium hydroxide, which acts as an osmotic laxative. It works by drawing water into the intestines, which helps to soften stools and stimulate bowel movements. The mechanism is effective for providing relief from occasional constipation by increasing intestinal water content, thereby making it easier to pass stools.

While it might seem like it could be related to the other options, Milk of Magnesia is not typically used to treat diarrhea, which would require different medications that might help to slow down bowel movements rather than stimulate them. For acid reflux, antacids formulated specifically to neutralize stomach acid are usually more appropriate. Additionally, headaches may respond to analgesics rather than a laxative like Milk of Magnesia. Therefore, the primary indication for Milk of Magnesia is indeed to relieve constipation.