How do antacids relieve heartburn?

Antacids relieve heartburn primarily by neutralizing gastric acid. When excess stomach acid enters the esophagus, it can lead to irritation and the sensation of heartburn. Antacids are basic compounds that can react with gastric acid to form water and other neutral products, effectively increasing the pH in the stomach and esophagus. This neutralization alleviates the burning sensation associated with heartburn.

This mechanism contrasts with options that involve increasing gastric acid secretion or blocking receptors linked to acid production, which would not help in relieving heartburn. Additionally, while promoting gastric emptying can be beneficial in some gastrointestinal conditions, it does not address the immediate issue of acid reflux and the symptoms it causes. Therefore, the key action of antacids lies in their ability to counteract acidity, thus providing symptomatic relief for those experiencing heartburn.