Antacids are over-the-counter medications used to relieve heartburn and indigestion by neutralizing stomach acid. They typically contain ingredients like magnesium hydroxide, aluminum hydroxide, or calcium carbonate, which help reduce acidity in the stomach. Antacids work quickly, providing fast relief from discomfort caused by excess stomach acid. These medications are available in various forms, including tablets, liquids, and chewables. While antacids can be effective for occasional heartburn, they are not intended for long-term use. If symptoms persist, it is advisable to consult a healthcare professional for further evaluation and treatment options.