Alka-Seltzer is a medication used to treat symptoms of heartburn, such as upset stomach and headache. While there are multiple products under this brand, this page focuses on the combination medication containing 3 active ingredients: citric acid, sodium bicarbonate, and aspirin. It comes as tablets that are dissolved in water. You drink the mixture by mouth, typically every 4-6 hours as needed.
Heartburn, indigestion, and sour stomach with headache, body aches, or pain
Upset stomach and headache from having too much food or drink
Headache, body aches, and pain alone
Alka-Seltzer is a combination of three medications:
Citric acid and sodium bicarbonate are antacids that work to relieve indigestion and upset stomach by neutralizing the acid in your stomach.
Aspirin is a non-steroidal inflammatory drug (NSAID) that stops the production of certain proteins in your body that cause pain and inflammation.
Source: DailyMed
Combination of three medications in a single pill
Easy to take for people who have trouble swallowing pills
Available over the counter
Might not be safe for children 12 years old and younger
Might need to take multiple times per day
Might not be safe for people with certain health conditions (e.g. kidney problems, heart problems, high bleeding risk)
Double check your medication label to make sure you have the right Alka-Seltzer product because there are several medications with similar brand names. They can contain different active ingredients with different directions.
It's best to dissolve Alka-Seltzer tablets in 4 ounces (half a cup) of room temperature water. Cold water will make the tablets dissolve slower and warm water can cause a lot of foaming.
Alka-Seltzer is only meant to give temporary relief of heartburn symptoms. Let your provider know if your symptoms worsen or last more than 10 days. They can check with you to see if you need a longer-lasting heartburn medication.
Because Alka-Seltzer contains aspirin, there's a chance this medication can raise your risk for stomach bleeds. Get medical help right away if you feel faint, vomit blood, have bloody or black stools, or have stomach pain that doesn't get better. These might be symptoms of stomach bleeds.
Tell your provider if you notice a ringing in the ears or loss of hearing after starting Alka-Seltzer. These are possible side effects of aspirin, one of the ingredients in Alka-Seltzer. If so, your provider will ask you to stop taking Alka-Seltzer. The ringing sound should go away and your hearing should return after you stop taking this medication.
Tell your provider or pharmacist about all the medications you're taking, especially if you're taking other NSAIDs, warfarin (Coumadin), or other blood thinners. Taking these with Alka-Seltzer can raise your risk of bleeding. Your provider will likely ask you to avoid these combinations, unless they think the benefits are greater than the risks of harm.
Alka-Seltzer contains 567 mg of sodium. Depending on what other health conditions you have, your provider might ask you to follow a low-sodium diet while taking this medication. If you have heart problems (e.g., heart failure) or kidney problems, ask your provider if Alka-Seltzer is right for you.
Alka-Seltzer can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: History of stomach bleeding or ulcers | Taking other NSAIDs, blood thinners, or corticosteroids while also taking Alka-Seltzer | Drinking 3 or more alcoholic beverages per day | Age 60 years or older | Taking Alka-Seltzer for a long time | Taking more Alka-Seltzer than instructed
Alka-Seltzer contains aspirin, which can irritate your stomach. This irritation can feel like stomach pain or heartburn. It can also lead to serious stomach problems, including bleeding and ulcers in this area. If you have stomach pain that doesn't get better; vomit or cough up blood or bits that look like coffee grounds; or have bloody or black, tarry stools; stop taking Alka-Seltzer and get medical attention right away. These can be signs of stomach bleeding or a stomach ulcer that your provider can help manage and treat.
Risk factors: Children recovering from chickenpox or flu-like symptoms
Aspirin use in children is linked to a rare but serious condition called Reye's syndrome. It typically occurs when children who are recovering from flu-like symptoms or other viruses use aspirin. Early symptoms of Reye's syndrome include vomiting, headache, confusion, and distress, but it can lead to seizures and loss of consciousness. Don't give Alka-Seltzer to a child who has a fever due to the flu. Ask your child's provider for medication recommendations for children who are sick.
Risk factors: NSAID allergy
Severe allergic reactions to Alka-Seltzer are possible, including anaphylaxis (closing of the throat). Call 911 if you experience hives, trouble breathing, or swelling of your lips or tongue. Let your provider know if you have an allergy to aspirin or other NSAIDs before you start taking Alka-Seltzer.
There are many different products under the brand name Alka-Seltzer. They can differ in active ingredients, strength, and direction. Refer to the manufacturer's label for directions that are specific to your product.
Some examples include:
Alka-Seltzer: Each dissolvable tablet contains 1,000 mg of citric acid, 325 mg of aspirin, and 1,916 mg of sodium bicarbonate.
Ages under 12 years: Ask your child's provider.
Ages 12 to 59 years: The typical dose is 2 tablets dissolved in 4 ounces of water, taken by mouth every 4 hours. The maximum dose is 8 tablets in 24 hours.
Ages 60 years and older: The typical dose is 2 tablets dissolved in 4 ounces of water, taken by mouth every 4 hours. The maximum dose is 4 tablets in 24 hours.
Alka-Seltzer Extra Strength: Each dissolvable tablet contains 1,000 mg of citric acid, 500 mg of aspirin, and 1,985 mg of sodium bicarbonate.
Ages under 12 years: Ask your child's provider.
Ages 12 to 59 years: The typical dose is 2 tablets dissolved in 4 ounces of water, taken by mouth every 6 hours. The maximum dose is 7 tablets in 24 hours.
Ages 60 years and older: The typical dose is 2 tablets dissolved in 4 ounces of water, taken by mouth every 6 hours. The maximum dose is 3 tablets in 24 hours.
Allergy to aspirin or another NSAID
Children younger than 12 years old
Heartburn, indigestion, and sour stomach with headache, body aches, or pain
Upset stomach and headache from having too much food or drink
Headache, body aches, and pain alone
Indigestion
Heartburn
Sour or upset stomach
Sour or upset stomach
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Bayer, Inc. (n.d.). Find the Alka-Seltzer® product that’s right for you.
Bayer, Inc. (n.d.). Frequently asked questions.
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Chapman, J., et al. (2023). Reye syndrome. StatPearls.
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Salisbury, B. H., et al. (2023). Antacids. StatPearls.
U.S. Food and Drug Administration. (2018). FDA Drug Safety Communication: FDA warns about serious bleeding risk with over-the-counter antacid products containing aspirin.
U.S. Food and Drug Administration. (2022). FDA recommends avoiding use of NSAIDs in pregnancy at 20 weeks or later because they can result in low amniotic fluid.
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