Gaviscon is an over-the-counter medication used to treat heartburn and acid indigestion. Unlike simple antacids that only neutralize stomach acid, Gaviscon works by forming a physical barrier that helps prevent acid from splashing up into your esophagus. It comes in both liquid and chewable tablet forms and is widely used for occasional reflux symptoms as well as more persistent acid-related discomfort.
How Gaviscon Works
Gaviscon contains alginate, a natural polymer derived from seaweed, along with bicarbonate and often calcium carbonate. When the alginate contacts the acid in your stomach, it rapidly forms a thick, gel-like layer that floats on top of your stomach contents. The bicarbonate produces small carbon dioxide bubbles, which help this gel rise to the surface and form what’s often called a “raft.” Calcium ions strengthen the raft’s structure by cross-linking the gel into a stable network.
This floating raft sits right at the top of your stomach, exactly where acid is most likely to escape upward into your esophagus. In patients with gastroesophageal reflux, researchers have observed that the raft localizes to the “acid pocket,” an unbuffered pool of acid that floats on top of food after a meal, and physically displaces it downward. The result is a mechanical barrier against reflux, not just a chemical one. The raft forms within seconds in laboratory settings and within a few minutes after you take it.
What It Treats
Gaviscon is primarily used for:
- Heartburn: That burning sensation behind your breastbone, especially after meals or when lying down.
- Acid indigestion: General discomfort in the upper stomach area caused by excess acid or acid in the wrong place.
- Acid reflux symptoms: Including a sour taste in the mouth, burping, or a feeling of food coming back up.
It’s particularly effective for postprandial reflux, the type that happens after eating. Because the raft forms on top of your meal, it targets the exact moment when reflux is most likely. Many people find it especially helpful at night, when lying flat makes it easier for acid to travel upward.
Gaviscon vs. Standard Antacids
Traditional antacids like calcium carbonate or magnesium hydroxide work by chemically neutralizing the acid already in your stomach. They can provide fast relief, but their effect is limited to however long the neutralizing ingredients last before being washed away by fresh acid production. A standard antacid may have a neutralizing capacity around 30 milliequivalents of acid per dose.
Gaviscon takes a different approach. While it does contain some acid-neutralizing ingredients (its neutralizing capacity is roughly 10 milliequivalents per half-maximal dose), its primary job is physical rather than chemical. The floating raft mechanically blocks acid from reaching your esophagus. This makes Gaviscon a better fit when your main problem is acid traveling upward rather than simply too much acid sitting in your stomach. For people whose heartburn is triggered by meals or worsened by bending over or lying down, the raft mechanism addresses the root issue more directly than neutralization alone.
How to Take It
Gaviscon works best when taken after meals and at bedtime, since those are the times reflux is most likely. The timing matters because the raft needs food in your stomach to float on top of. Taking it on a completely empty stomach reduces its effectiveness.
For the regular strength liquid, the typical adult dose is one to two tablespoonfuls up to four times a day, with a maximum of eight tablespoonfuls in 24 hours. The extra strength liquid uses a smaller volume per dose: two to four teaspoonfuls up to four times daily, with a 16-teaspoon daily maximum. If you’re using chewable tablets, chew them thoroughly rather than swallowing them whole, since the alginate needs to be broken down before it reaches your stomach to form the raft properly.
If you experience heartburn frequently, you can take Gaviscon up to four times a day. For occasional symptoms, a single dose after the meal that triggered your discomfort is often enough.
Who Should Be Cautious
Gaviscon is generally well tolerated, but certain formulations contain meaningful amounts of sodium. If you’re on a sodium-restricted diet due to high blood pressure, heart failure, or kidney problems, check the label carefully or choose a low-sodium version. Some formulations also contain aluminum or magnesium compounds, which can cause constipation or loose stools respectively in some people.
Gaviscon is one of the more commonly recommended options for heartburn during pregnancy, since the alginate raft mechanism doesn’t require systemic absorption the way some other medications do. That said, formulations vary by country and brand, so it’s worth confirming which specific version is appropriate if you’re pregnant or breastfeeding.
If you find yourself needing Gaviscon daily for more than two weeks, that’s a signal your reflux may need a different treatment approach. Persistent symptoms could indicate gastroesophageal reflux disease (GERD), which may benefit from acid-suppressing medications that reduce acid production at the source rather than blocking it after the fact.
What Gaviscon Won’t Do
Gaviscon is designed for symptom relief, not for healing damage that’s already occurred. If acid reflux has irritated or inflamed your esophageal lining, the raft can help prevent further exposure, but it won’t actively repair the tissue the way prescription acid suppressants can over time. It also won’t address the underlying causes of chronic reflux, such as a weakened lower esophageal sphincter or a hiatal hernia. Think of it as a reliable tool for managing occasional or mild symptoms rather than a long-term solution for a structural problem.