What is the primary action of antacids?

The primary action of antacids is to neutralize stomach acid. Antacids are typically composed of alkaline substances that react with gastric acid in the stomach, effectively raising the pH level and helping to relieve symptoms of heartburn, indigestion, and upset stomach caused by excessive acidity. This neutralization can provide immediate symptomatic relief by reducing the acidity that irritates the stomach lining and esophagus.

While some other options may relate to supportive actions in gastrointestinal care—such as nausea management or pain relief—they do not encapsulate the fundamental purpose of what antacids are designed to do. Antacids specifically target the acid in the stomach, making option B the most accurate choice.