For heartburn that strikes once in a while, a calcium carbonate antacid like Tums or Rolaids works fastest. For heartburn that shows up two or more days a week, omeprazole (Prilosec OTC), a proton pump inhibitor, is the over-the-counter option pharmacists reach for most, and famotidine (Pepcid AC) sits in between as a same-day option that lasts longer than an antacid. None of the three is universally "best." The right one depends on how often your reflux happens and how fast you need it gone.

Acid reflux is one of the most self-treated conditions on a pharmacy shelf, and also one of the most mismatched. Patients reach for whatever they have always used, even when the actual pattern of their symptoms has changed. This guide breaks down what each OTC category genuinely does, when a supplement like DGL licorice or mastic gum earns a real place next to the antacids, and exactly when reflux stops being a problem a pharmacy can solve on its own. For the wider picture on self-care choices beyond reflux specifically, our complete guide to over-the-counter medicines covers the full OTC aisle drug by drug.

Antacids, H2 Blockers, and PPIs: What Each One Actually Does

Three categories of OTC medicine treat acid reflux, and each one interrupts the problem at a different point in the chain. Matching the category to your actual pattern of heartburn matters far more than brand loyalty.

Antacids such as calcium carbonate (Tums) and magnesium hydroxide (Maalox) neutralize acid that is already sitting in your stomach. They start working within minutes, which makes them the right call for an occasional flare after a heavy meal, but the relief rarely lasts past an hour or two. H2 blockers, mainly famotidine (Pepcid AC), block the histamine signal that tells your stomach to make acid in the first place. They take roughly 15 to 60 minutes to kick in and can cover you for up to 12 hours, so they work well taken ahead of a meal you already know will trigger you. Proton pump inhibitors, led by omeprazole (Prilosec OTC), shut down the acid pump itself instead of just one signal feeding it. They are the strongest of the three, but they are not a rescue product. The label is explicit that omeprazole is not intended for immediate relief and may take one to four days to reach its full effect.^[3]

Antacids: Fast Relief With a Short Clock

Antacids are the product most people already have in a kitchen drawer, and for good reason. They are the fastest thing on the shelf, even if they are also the shortest acting.

Calcium carbonate and magnesium hydroxide both work the same basic way. They are mild bases that react directly with the acid already in your stomach, lowering the burn within minutes rather than preventing the next wave of acid from forming. Take them with food or right after eating, since that is when reflux is most likely and when the antacid has the most acid available to neutralize.

In my experience at the pharmacy counter, the patients who get the least value from antacids are the ones taking them on a strict daily schedule like a maintenance medicine. That is not what they are built for. Calcium-based antacids can cause constipation at high doses, magnesium-based ones can cause the opposite, and anyone with reduced kidney function should check with a pharmacist before regular use, since both minerals are cleared through the kidneys.

Famotidine and Omeprazole: When Reflux Happens More Than Twice a Week

Once heartburn stops being occasional, the product needs to change with it. Famotidine and omeprazole both work ahead of the burn rather than after it.

Famotidine blocks histamine receptors on the cells that produce stomach acid, cutting the supply before it builds up. It takes effect within an hour and keeps working for up to 12 hours, long enough to cover a problem dinner and the hours afterward. Many people use it the way I recommend: 15 to 30 minutes before the meal they already know will set them off, rather than waiting for the burning to start.

Omeprazole works further upstream, blocking the actual proton pump inside the cells that manufacture acid. But it is built around a 14-day course, not a single dose. The Prilosec OTC label is direct about this: it treats heartburn that occurs two or more days a week, it is not intended for immediate relief, and it can take one to four days before you feel the full benefit.^[3] Patients frequently ask me whether they can just keep taking it every single day past two weeks since it never asks for a prescription, and my answer is always: the label caps a course at 14 days and limits repeat courses to once every four months unless a doctor says otherwise, and that limit exists for a reason.

The reason is fracture risk. The FDA has flagged a possible increased risk of hip, wrist, and spine fractures tied to long-term or high-dose proton pump inhibitor use, mostly in people taking them for a year or longer.^[4] Short courses at the OTC dose are not where that risk shows up. Repeating course after course without ever seeing a doctor is.

Where DGL Licorice and Mastic Gum Actually Fit In

Neither of the two supplements below replaces an antacid mid-burn or a PPI for frequent reflux. But they earn a place on the shelf for a different reason: supporting the lining that the acid is irritating in the first place.

Deglycyrrhizinated licorice, sold as DGL, is licorice root with the compound responsible for raising blood pressure (glycyrrhizin) removed. What remains appears to support the stomach and esophagus's own mucus layer rather than reducing acid directly. A randomized, placebo-controlled trial on a standardized DGL extract found a clinically significant improvement in heartburn and regurgitation scores starting from the second week of treatment, with quality of life scores improving more than in the placebo group.^[5]

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Mastic gum works through a different route entirely. It is a resin from the Pistacia lentiscus tree, and laboratory studies, including one published in the New England Journal of Medicine, have shown it kills Helicobacter pylori directly, the same bacteria responsible for a meaningful share of stubborn gastritis and reflux that does not respond well to antacids alone.^[6] If a doctor has confirmed H. pylori as part of your reflux picture, mastic gum is one of the few supplements with laboratory evidence specifically against that organism, rather than general digestive marketing language.

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What Makes Reflux Worse: NSAIDs, Trigger Foods, and Timing

Picking the right medicine only helps if you are not simultaneously feeding the problem. A handful of everyday habits undo a perfectly good antacid or PPI faster than people expect.

Fatty meals slow stomach emptying and leave more acid sitting around longer than usual. Caffeine, alcohol, chocolate, and carbonated drinks relax the same valve that is already not closing properly in people with reflux.^[1] Lying down within a few hours of eating gives gravity nothing to work with, which is why raising the actual head of the bed by 10 to 20 centimetres helps more than stacking extra pillows, since extra pillows just add pressure on your stomach instead of elevating your chest.^[1]

NSAIDs deserve their own warning. Ibuprofen, naproxen, and aspirin irritate the stomach lining directly, on top of whatever reflux is already doing to your esophagus, and the combination is worse than either problem alone.

But the lesson for reflux specifically is simpler than the painkiller question itself. If you already deal with regular heartburn and you need a painkiller, paracetamol is the gentler choice on your stomach. Save ibuprofen for short courses, taken with food, and tell your pharmacist if you are also on a regular reflux medicine.

When Acid Reflux Stops Being a Pharmacy Problem

Most heartburn is genuinely a self-care situation. A smaller number of cases are something else wearing a heartburn costume.

See a doctor rather than reaching for another OTC product if any of the following apply:

• Heartburn persists beyond two to three weeks of consistent antacid, famotidine, or omeprazole use
• Food or pills feel like they are sticking on the way down (dysphagia)
• Unexplained weight loss alongside reflux symptoms
• Vomiting blood, or material that looks like coffee grounds
• Chest pain that is not clearly tied to eating or position, since reflux and heart-related pain can feel similar^[2]

Any one of these crosses the line from self-treatable into something an endoscopy or a doctor's exam should rule out, particularly for anyone over 50, anyone with a long personal history of reflux, or anyone whose symptoms have changed character recently rather than just frequency.^[1][2]

And if what actually shows up alongside your reflux is active vomiting rather than the burning sensation itself, the approach shifts. Our guide to the best OTC medicine for vomiting covers rehydration and the antiemetics that matter once fluid loss becomes the bigger concern. The same goes the other direction: if your queasiness only ever shows up with travel rather than with meals, you are more likely dealing with motion sickness rather than reflux, and that guide covers the antihistamines and ginger options that actually address that specific mechanism.

Myth vs Fact: What People Get Wrong About Acid Reflux Medicine

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References

1. NHS. Heartburn and acid reflux. nhs.uk
2. Cleveland Clinic. Acid Reflux & GERD: Symptoms, Causes, Treatment. my.clevelandclinic.org
3. U.S. FDA. Prilosec OTC (omeprazole magnesium) Drug Facts label. accessdata.fda.gov
4. U.S. FDA. Drug Safety Communication: Possible increased risk of fractures of the hip, wrist, and spine with the use of proton pump inhibitors. fda.gov
5. Efficacy and Safety of GutGard® in Managing Gastroesophageal Reflux-Related Symptoms: A Phase III, Double-Blind, Randomized Placebo-Controlled Trial. PMC. pmc.ncbi.nlm.nih.gov
6. Huwez FU, Thirlwell D, Cockayne A, Ala'Aldeen DAM. Mastic gum kills Helicobacter pylori. N Engl J Med. 1998. nejm.org
7. Mayo Clinic. Omeprazole (oral route): Description and dosage. mayoclinic.org