Maalox neutralizes acid that is already sitting in your stomach. Gaviscon neutralizes acid too, but it also forms a floating gel raft that physically blocks acid from splashing back up into your esophagus, so the two are not interchangeable even though they sit on the same pharmacy shelf.

Patients frequently ask me whether it actually matters which one they grab, and my answer is always the same: it depends on what your heartburn is doing. If the burn just needs neutralizing after a heavy meal, either product works. But if it strikes the moment you lie down or bend forward, one of these two has a mechanical trick the other simply does not.

What Maalox and Gaviscon Actually Do Inside Your Stomach

Both products start the same way. From there, the mechanisms split, and that split is the entire reason this comparison exists.

Maalox contains aluminum hydroxide and magnesium hydroxide, usually alongside simethicone for gas.^[1] These are mild bases. They react directly with the hydrochloric acid already sitting in your stomach, lowering the burn within minutes. Nothing about that reaction stops your stomach from producing more acid a few minutes later.

Gaviscon works differently at its core. Alongside similar neutralizing minerals, most formulations also contain sodium alginate.^[2] The moment alginate meets stomach acid, it thickens into a gel. Carbon dioxide released by the accompanying bicarbonate gets trapped inside that gel, and the whole thing floats to the top of your stomach contents like a raft on water.^[3] That raft sits above the acid and physically blocks it from splashing into your esophagus, which matters most when you lie down, bend forward, or exercise on a full stomach.

Maalox: Straightforward Neutralizing, Plus Relief From Gas

That barrier difference does not make Maalox the weaker option. It just makes it the right tool for a different job.

In my experience at the pharmacy counter, Maalox earns its shelf space with patients dealing with heartburn and bloating together after a heavy meal, not heartburn on its own. The simethicone component does nothing to acid. It works on trapped gas bubbles, merging small ones into larger ones that pass more easily, which is why Maalox often feels like it is doing more than a plain antacid when a meal leaves you both burning and uncomfortably full.

Maalox's aluminum content tends to slow the gut, so it can cause constipation with regular use. And anyone with reduced kidney function should be cautious with repeated dosing, since both aluminum and magnesium clear through the kidneys and can build up over time.^[4]

Gaviscon: The Raft That Keeps Working After You Lie Down

Gaviscon earns its place for a narrower reason than Maalox, but a more specific one.

From what I see in practice, this is the antacid I point patients toward when their heartburn strikes specifically at night or right after bending over, because the alginate raft keeps blocking reflux even after the neutralizing minerals inside it have been used up. The raft forms within seconds of contact with stomach acid and can keep floating for up to four hours, considerably longer than the plain neutralizing action Maalox offers on its own.^[3]

Gaviscon does carry meaningful sodium, which matters for anyone managing blood pressure on a sodium-restricted diet, and the exact mineral pairing (magnesium carbonate rather than magnesium hydroxide in most markets) varies by formulation, so it is worth reading the specific label in front of you rather than assuming every box is identical.^[5]

I bring that story up here because the same reflex shows up with antacids, just with less obvious stakes. Patients grab whichever box is closest without checking what it is actually built to do, and most of the time that works fine. But when the wrong mechanism meets the wrong symptom night after night, the relief never quite lands, and nobody stops to ask why.

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Maalox itself was not found listed for sale on iHerb at the time of writing, so no affiliate link is included for it here. Product URL not verified. It remains widely available at pharmacies and supermarkets in Nigeria and internationally.

Which One Should You Actually Reach For?

Put the mechanism together with your own pattern of symptoms, and the choice mostly makes itself.

Reach for Maalox when a meal leaves you burning and bloated at the same time and you need relief now, not for the whole night. Reach for Gaviscon when the heartburn specifically strikes once you lie down, bend forward, or exercise on a full stomach, since that is exactly the scenario its raft was designed for.

And if you have already tried an antacid a couple of times a day for more than two weeks without real improvement, neither product is the fix anymore. That pattern calls for famotidine or a supervised course of omeprazole instead, which our full guide to OTC medicine for acid reflux breaks down category by category, including when DGL licorice or mastic gum genuinely earn a place alongside either one.

What Maalox and Gaviscon Have in Common: Same Limits, Same Interactions

But mechanism aside, Maalox and Gaviscon share the same practical ceiling.

Neither is meant for daily maintenance use beyond about two weeks without medical input,^[4] and both can bind to certain medicines in your gut before your body gets the chance to absorb them properly. One thing I always check when a patient brings me either product alongside a new prescription is timing. Tetracycline and fluoroquinolone antibiotics, iron supplements, and levothyroxine all lose a meaningful share of their effectiveness if taken within two hours of an antacid, Maalox or Gaviscon included.^[6]

Our guide on taking two different antacids at the same time covers this interaction pattern in more depth, including what happens if you stack a calcium-based product like Tums on top of either one. If heartburn has become a near-daily habit rather than an occasional flare, that pattern is worth a closer look on its own; our guide on taking antacids for three months daily walks through exactly when that calls for a doctor rather than another box.

In Nigeria, check for a valid NAFDAC registration number on any antacid pack you buy locally, alongside the international brand name you already recognise. Our guide on what a NAFDAC number means and how to verify it walks through that two-minute check.

Myth vs. Fact: Maalox and Gaviscon

Frequently Asked Questions

The full Over-the-Counter Medicines: The Complete Guide covers where antacids fit alongside every other category on the OTC shelf.

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References

1. DailyMed, U.S. National Library of Medicine. Maalox Antacid (aluminum hydroxide, magnesium hydroxide, simethicone) drug facts label. dailymed.nlm.nih.gov
2. DailyMed, U.S. National Library of Medicine. Gaviscon (aluminum hydroxide and magnesium carbonate) drug facts label. dailymed.nlm.nih.gov
3. Mandel KG, et al. Review article: alginate-raft formulations in the treatment of heartburn and acid reflux. Alimentary Pharmacology & Therapeutics. pubmed.ncbi.nlm.nih.gov
4. NHS. Heartburn and acid reflux. nhs.uk
5. MedlinePlus, National Library of Medicine. Antacids. medlineplus.gov
6. MedlinePlus, National Library of Medicine. Antacids: drug interactions. medlineplus.gov