Stay Connected

Want to receive tips, personalized content and exclusive offers from PEPCID®? Sign up for PEPCID® emails today!

The information you submit will be governed by our Privacy Policy and you agree to the Financial Incentive Notice.

What Are Antacids?

What Are Antacids?

Antacids are medications that help fight heartburn — that burning pain you may feel in your chest after a large, spicy, or fatty meal. Heartburn is a symptom of acid reflux. This condition happens when the acid and undigested food normally found in your stomach leaks back into your esophagus, the tube that connects your stomach to your mouth. When acid reflux occurs frequently, it is called gastroesophageal reflux disease (GERD).

What Are Antacids Used For?

Antacids are often taken to relieve heartburn, acid indigestion and sour stomach, as well as for relief of upset stomach associated with these symptoms.

How Do Antacids Work?

Antacids are bases — the chemical opposite of an acid. When you add a base to an acid-containing liquid such as stomach juices, the fluid becomes less acidic. In this way, antacids prevent the stomach contents from getting too acidic, and reduce the chances that the acid will travel up into the esophagus.

These medications may also have other effects that help prevent heartburn1.

Each antacid medication contains one or more active ingredients. These compounds usually work by neutralizing acid in the stomach1. The most common active ingredients in antacids include:

Calcium Carbonate

Antacid tablets that contain calcium carbonate have acid-neutralizing powers1.

Calcium carbonate also has an effect on the lower esophageal sphincter (LES), the muscle that blocks off the esophagus from the stomach. Acid reflux can happen when the LES becomes too relaxed. However, calcium carbonate can tighten the LES, helping the stomach contents remain in place1.

Calcium has another heartburn-relieving benefit — it increases muscle contractions in the esophagus. When these muscles contract, they push acid back down into the stomach, helping keep the esophagus clear1.

Magnesium Hydroxide

This compound can help decrease the amount of acid in the stomach by neutralizing acid.

Aluminum Hydroxide

Aluminum hydroxide works in a similar way as calcium carbonate.

Antacid Medications

There are several types of antacid medications that work in different ways to reduce stomach acid.

Antacid Only

Many over-the-counter heartburn medications only contain antacid compounds — calcium carbonate, magnesium hydroxide, or aluminum hydroxide.

Combination Antacid & H2 Blocker: PEPCID COMPLETE®

Medications like PEPCID COMPLETE® contain multiple types of active ingredients that work to fight heartburn on several levels.

H2 blockers such as famotidine are also common heartburn relievers. These medications directly block parietal cells, the acid-producing cells inside the stomach. H2 blockers stop these cells from making additional stomach acid, which helps stop extra acid from escaping into the esophagus2.

PEPCID COMPLETE® combines the acid-suppressing power of an H2 blocker with the acid-neutralizing abilities of calcium carbonate. Watch a video to see how PEPCID COMPLETE® works:

PEPCID COMPLETE® works fast to relieve heartburn and control acid all day or all night.*

  • 1Salisbury BH, Terrell JM. Antacids. StatPearls. Updated August 21, 2021. Accessed December 16, 2021.
  • 2Engevik AC, Kaji I, Goldenring JR. The Physiology of the Gastric Parietal Cell. Physiol Rev. 2020;100(2):573-602.

Our Heartburn Relief Products

Pepcid vs PPI and Antacid
H2 Blocker vs. Antacid vs. PPI
Pepcid AC Maximum Strength, Pepcid Complete, Pepcid Complete Travel, and Pepcid AC Original Strength
What Is PEPCID®?
Pepcid famotidine
What Is Famotidine?
Pepcid logo versus other over-the-counter heartburn relief medication
Compare Heartburn Treatments