Magnesium hydroxide is widely used as an antacid to neutralize stomach acid, providing relief from conditions like heartburn, indigestion, and acid reflux. It works by reacting with hydrochloric acid in the stomach to form magnesium chloride and water, effectively reducing acidity. In the medical field, it is also employed as a laxative to alleviate constipation by drawing water into the intestines, promoting bowel movements.

In industrial applications, it serves as a flame retardant in plastics, rubber, and textiles due to its ability to release water when heated, which helps to cool and suppress flames. Additionally, it is used in wastewater treatment to neutralize acidic waste and remove heavy metals by precipitating them as hydroxides. In the food industry, it acts as a pH regulator and stabilizer in products like canned vegetables and tofu, and serves as a magnesium source. It is also utilized in personal care products such as toothpaste and deodorants for its antibacterial properties and ability to reduce unpleasant odors. Its versatility and safety make it a valuable compound across various sectors.