Alka-Seltzer can relieve heartburn, but which box you pick matters. Original Alka-Seltzer contains aspirin (325 mg per tablet), a painkiller that can irritate the stomach and isn’t a good choice for heartburn on its own. Alka-Seltzer Heartburn Relief contains no aspirin: it’s citric acid and sodium bicarbonate, which fizz in water into an antacid solution. The Heartburn + Gas ReliefChews are a calcium carbonate antacid with simethicone for gas. All the effervescent versions contain a lot of sodium, about 570 to 590 mg per tablet.
Alka-Seltzer is one of the most confusing brands on the heartburn shelf because the same name covers a painkiller-antacid combination, a pure antacid, chewables and cold remedies. Below I compare the main versions, explain why the aspirin matters for anyone with a sensitive stomach, cover the sodium issue, and look at how it fits if you have reflux or silent reflux.
Key Takeaways
- Original Alka-Seltzer (Antacid & Pain Relief): aspirin 325 mg, citric acid 1,000 mg and sodium bicarbonate 1,916 mg per tablet. It’s for pain plus an upset stomach, not plain heartburn.
- Alka-Seltzer Heartburn Relief: citric acid 1,000 mg and sodium bicarbonate (about 1,940 mg) per tablet, with no aspirin.
- Heartburn + Gas ReliefChews: calcium carbonate 750 mg plus simethicone 80 mg per chew. No fizzing, no aspirin.
- Aspirin, like other NSAIDs, can cause stomach irritation, ulcers and bleeding. The Original label carries a stomach bleeding warning.
- The effervescent tablets contain roughly 570 to 590 mg of sodium each. Ask a doctor first if you’re on a sodium-restricted diet or have heart, kidney or blood pressure problems.
- Typical heartburn dose: 2 tablets dissolved in 4 oz of water every 4 hours as needed, no more than 8 in 24 hours (4 if you’re 60 or over), and no longer than 2 weeks at the maximum dose.
- The fizz itself adds gas, which can cause burping and bloating.
- For frequent heartburn or silent reflux, an alginate or acid reducer and diet changes are better options.
The Main Alka-Seltzer Versions Compared
| Product | Active ingredients (per tablet) | Aspirin? | Sodium | Best for |
|---|---|---|---|---|
| Original (Antacid & Pain Relief) | Aspirin 325 mg, citric acid 1,000 mg, sodium bicarbonate 1,916 mg | Yes | About 568 mg | Headache or body aches with an upset stomach |
| Heartburn Relief (effervescent) | Citric acid 1,000 mg, sodium bicarbonate about 1,940 mg | No | About 575 to 586 mg | Occasional heartburn and acid indigestion |
| Heartburn + Gas ReliefChews | Calcium carbonate 750 mg, simethicone 80 mg | No | Low | Heartburn with gas or bloating |
Figures are from the Drug Facts labels for aspirin-containing Alka-Seltzer, Alka-Seltzer Heartburn and Alka-Seltzer Heartburn Relief Lemon Lime. Sodium bicarbonate amounts vary slightly between flavors. Alka-Seltzer Plus cold and flu products are different medicines again and aren’t for heartburn.
The quick rule
If the box mentions pain relief, aspirin, “Original” or “Extra Strength” pain relief, it contains aspirin. For heartburn alone, look for “Heartburn Relief” on the front and check the Drug Facts panel for the word aspirin.
Why the Aspirin Matters
Aspirin is a nonsteroidal anti-inflammatory drug (NSAID). NSAIDs reduce the prostaglandins that protect the stomach lining, which is why they’re a leading cause of gastritis, ulcers and stomach bleeding. The American College of Gastroenterology has published guidelines specifically on preventing NSAID-related ulcer complications [Lanza et al., American Journal of Gastroenterology, 2009].
The Original Alka-Seltzer label warns of severe stomach bleeding, with higher risk if you’re 60 or older, have had ulcers or bleeding, take blood thinners or steroids, take other NSAIDs, or have 3 or more alcoholic drinks a day. It also carries a Reye’s syndrome warning for children and teenagers with chickenpox or flu-like symptoms. Taking an aspirin product for heartburn is, in effect, treating stomach irritation with something that can cause it. See do NSAIDs cause reflux? and low-dose aspirin and acid reflux.
How Alka-Seltzer Heartburn Relief Works
When you drop the tablets in water, the citric acid and sodium bicarbonate react, which is the fizz. What’s left after the bubbling stops is mainly sodium citrate and leftover sodium bicarbonate, an alkaline solution that neutralizes stomach acid within minutes. It’s essentially a measured, better-tasting version of baking soda for heartburn.
Like any antacid, the relief is fast but short-lived. Antacids typically neutralize acid for about an hour [Feldman, JAMA, 1996].
How to take it
- Fully dissolve 2 tablets in 4 oz of water and let the fizzing stop before drinking.
- Adults and children 12 and over: 2 tablets every 4 hours as needed, no more than 8 tablets in 24 hours.
- Adults 60 and over: no more than 4 tablets in 24 hours.
- Don’t use the maximum dose for more than 2 weeks without a doctor’s advice.
- Ask a pharmacist if you take prescription medicines, as antacids can affect their absorption.
The Sodium Problem
Each effervescent tablet contains about 570 to 590 mg of sodium, so a standard 2-tablet dose provides over 1,100 mg. That’s about half the 2,300 mg daily limit in US dietary guidelines from one dose. At the 8-tablet maximum, you’d get well over the whole day’s limit from Alka-Seltzer alone.
That matters if you have high blood pressure, heart failure, kidney disease, or swelling, or if you’re pregnant. The label says to ask a doctor first if you’re on a sodium-restricted diet. The ReliefChews are a lower-sodium alternative, since they use calcium carbonate instead.
Alka-Seltzer and Reflux: Does the Fizz Help or Hurt?
Carbonation releases gas in the stomach, which can cause burping and bloating and, for some people, push more stomach contents upward. Letting the fizzing stop completely before you drink reduces this but doesn’t remove it entirely. See seltzer and club soda for acid reflux and do antacids cause burping and gas?
For silent reflux (LPR), antacids don’t stop stomach contents, including pepsin, reaching the throat. An alginate such as Gaviscon Advance, which forms a protective raft, and a low-acid diet are more useful. See alginates for acid reflux.
Alka-Seltzer for a Hangover With Heartburn
Original Alka-Seltzer is often used for hangovers because it combines a painkiller with an antacid. But alcohol already irritates the stomach lining, and adding aspirin increases the risk of stomach bleeding, especially after heavy drinking. The label specifically lists 3 or more drinks a day as a risk factor. If you have a hangover with heartburn, the aspirin-free Heartburn Relief version for the stomach is the safer choice. Acetaminophen (paracetamol) is gentler on the stomach for the headache, but it carries its own liver risks after heavy drinking, so ask a pharmacist.
Better Options for Frequent Heartburn
- Longer relief: famotidine (Pepcid) lasts many hours. See Pepcid AC vs Pepcid Complete.
- Lower-sodium antacids: calcium carbonate products. See Tums vs Rolaids.
- Night-time reflux: an alginate at bedtime
- Frequent heartburn (2 or more days a week): a short PPI course or a doctor’s review. See what is an antacid? for how the different types compare.
When to See a Doctor
- Heartburn on more than 2 days a week, or needing the maximum dose for 2 weeks
- Difficulty swallowing, vomiting blood, or black stools
- Unexplained weight loss
- Chest pain with exertion, breathlessness, sweating, or pain spreading to the arm or jaw. See heartburn or heart attack?
Conclusion
Alka-Seltzer can relieve heartburn quickly, but only some versions are suited to it. Original Alka-Seltzer contains 325 mg of aspirin per tablet and carries a stomach bleeding warning, so it’s not a good heartburn remedy. Alka-Seltzer Heartburn Relief is aspirin-free and works as a fast antacid, but contains around 570 to 590 mg of sodium per tablet. The ReliefChews avoid both the aspirin and the high sodium. Whichever you choose, it’s a short-acting fix for occasional heartburn.
If you’re reaching for antacids regularly, the bigger win is reducing how much reflux you have in the first place, and that comes down mostly to what and when you eat. The Wipeout Diet Plan gives you a step-by-step, low-acid way to eat. I built it around LPR, the hardest form of reflux to control, and it works just as well for GERD and everyday heartburn.
Frequently Asked Questions
Does Alka-Seltzer help heartburn?
Yes. Alka-Seltzer Heartburn Relief neutralizes stomach acid within minutes. Choose the heartburn version rather than Original, which contains aspirin.
Does Alka-Seltzer have aspirin in it?
Original Alka-Seltzer and the pain relief versions contain aspirin (325 mg per tablet). Alka-Seltzer Heartburn Relief and the Heartburn + Gas ReliefChews don’t.
How much sodium is in Alka-Seltzer?
The effervescent tablets contain roughly 570 to 590 mg of sodium each, depending on the version, so a 2-tablet dose provides over 1,100 mg.
Can I take Alka-Seltzer every day?
It isn’t meant for daily long-term use. Don’t use the maximum dose for more than 2 weeks, and see a doctor if you have heartburn on more than 2 days a week.
Is Alka-Seltzer safe during pregnancy?
Avoid aspirin-containing versions unless a doctor advises otherwise, and check with your provider about the high-sodium heartburn tablets. Calcium carbonate antacids are often preferred in pregnancy.
Is Alka-Seltzer or Tums better for heartburn?
Both relieve heartburn quickly. Tums (calcium carbonate) is lower in sodium and doesn’t fizz. Alka-Seltzer Heartburn Relief is liquid once dissolved, which some people find soothing, but it’s high in sodium.
Can Alka-Seltzer make reflux worse?
The carbonation can cause burping and bloating, which may worsen reflux for some people. Let the fizzing stop completely before drinking, or use the chewables instead.
Research & References
- The US Drug Facts label for aspirin-containing Alka-Seltzer (aspirin 325 mg, citric acid 1,000 mg, sodium bicarbonate 1,916 mg; 568 mg sodium), including stomach bleeding and Reye’s syndrome warnings [Alka-Seltzer label].
- The US Drug Facts label for Alka-Seltzer Heartburn (citric acid 1,000 mg, sodium bicarbonate 1,940 mg; 575 mg sodium), including dosing limits and the sodium-restricted diet warning [Alka-Seltzer Heartburn label].
- The US Drug Facts label for Alka-Seltzer Heartburn Relief Lemon Lime (citric acid 1,000 mg, sodium bicarbonate 1,976 mg; 586 mg sodium) [Alka-Seltzer Heartburn Relief label].
- American College of Gastroenterology guidelines on preventing NSAID-related ulcer complications [Lanza et al., American Journal of Gastroenterology, 2009].
- A randomized crossover trial finding that a calcium carbonate antacid neutralized acid within 30 minutes but lasted about 60 minutes [Feldman, JAMA, 1996].
David Gray
12 years living with LPR · Consultant & researcher
I've lived with LPR for twelve years — the misdiagnoses, the PPI courses that did nothing, the slow work of figuring out what actually helps. Wipeout Reflux is where I translate the research into plain terms for people stuck in the same place. Every claim here is sourced to peer-reviewed work, and I consult one-to-one with LPR sufferers.