Milk of magnesia:
Magnesium hydroxide is an inorganic compound with the chemical formula Mg(OH)2. As a suspension in water, it is often called milk of magnesia because of its milk-like appearance. The solid mineral form of magnesium hydroxide is known as brucite.
Uses:Suspensions of magnesium hydroxide in water (milk of magnesia) are used as an antacid to neutralize stomach acid, and a laxative. The diarrhea caused by magnesium hydroxide carries away much of the body's supply of potassium, and failure to take extra potassium may lead to muscle cramps. Magnesium hydroxide is also used as an antiperspirant armpit deodorant Milk of magnesia is useful against canker sores (aphthous ulcer) when used topically. It is primarily used to alleviate constipation, but also to relieve indigestion and heartburn. When taken orally as a laxative, the osmotic force of the magnesia suspension acts to draw fluids from the body and to retain those already within the lumen of the intestine, serving to distend the bowel, thus stimulating nerves within the colon wall, inducing peristalsis and resulting in evacuation of colonic contents. It is also used as an antacid, though more modern formulations combine the antimotility effects of equal concentrations of aluminum hydroxide to avoid unwanted laxative effects.