Gaviscon is not a proton pump inhibitor. It is classified as an antacid, and many formulations also contain sodium alginate, which works through an entirely different mechanism than PPIs. The two products treat similar symptoms, particularly heartburn and acid reflux, but they do so in fundamentally different ways.
How Gaviscon Works
Gaviscon’s active ingredients are aluminum hydroxide and magnesium carbonate, both of which neutralize stomach acid on contact. In the U.S. regular strength formulation, each dose contains 95 mg of aluminum hydroxide and 358 mg of magnesium carbonate. This is straightforward acid neutralization: the ingredients chemically react with hydrochloric acid in your stomach and make it less acidic.
Many Gaviscon products (particularly those sold in the UK and Europe) also contain sodium alginate, which does something more unusual. When alginate meets stomach acid, the carbonate ingredients release carbon dioxide gas. At the same time, the alginate molecules link together into a gel-like network. The trapped gas bubbles turn this gel into a buoyant foam that floats on top of your stomach contents, forming what’s called a “raft.” If reflux happens, the raft rises into your esophagus first instead of acid, acting as a physical barrier. This effect is immediate and works regardless of how much acid your stomach is producing.
How PPIs Work Differently
Proton pump inhibitors, such as omeprazole and lansoprazole, take an entirely different approach. Instead of neutralizing acid after it’s been made, they block the enzyme responsible for producing it in the first place. This enzyme, sometimes called the proton pump, drives the chemical reaction that creates stomach acid. By shutting it down, PPIs reduce acid production at the source.
The tradeoff is speed versus duration. PPIs take days of regular use to reach their full effect, but once they do, they suppress acid production around the clock. Gaviscon provides relief within minutes but wears off relatively quickly. If you eat a spicy meal and get sudden heartburn, Gaviscon is the faster option. If you have chronic, recurring acid reflux that disrupts your daily life, a PPI is generally more effective for long-term control.
When Each One Makes More Sense
Gaviscon fits best for moderate reflux that flares up occasionally, especially after meals. The alginate raft specifically targets the “acid pocket,” a pool of highly acidic fluid that sits on top of your stomach contents after eating and is a common trigger for postmeal heartburn. Because Gaviscon works locally in the stomach and isn’t absorbed into your bloodstream in a meaningful way, it’s considered a non-systemic treatment with a lighter side-effect profile.
PPIs are the stronger option when reflux is persistent, when there’s visible damage to the esophagus, or when symptoms don’t respond to simpler treatments. Clinical guidelines generally reserve PPIs for these more serious or ongoing cases. While PPIs are well tolerated overall, prolonged use has been linked to a modest increase in the risk of certain infections and bone fractures, which is one reason clinicians prefer not to prescribe them when a milder option would work.
Can You Take Gaviscon With a PPI?
Yes. According to the NHS, you can safely take Gaviscon alongside a prescribed PPI like lansoprazole. This combination actually makes practical sense: the PPI handles baseline acid suppression throughout the day, while Gaviscon provides on-demand relief for breakthrough symptoms, particularly after meals. A clinical trial comparing the two (the GOOD trial) found that Gaviscon paired well with on-demand PPI use for people with moderate reflux, potentially reducing the need for continuous PPI prescriptions.
If you’re currently taking a PPI and still getting occasional heartburn, adding Gaviscon as needed is a reasonable approach. The two products work through completely separate mechanisms, so they don’t interfere with each other.