DISCLAIMER: This information on this site is for guidance only. It is not a substitute for professional medical care by a qualified doctor or other health care professional. ALWAYS check with your doctor if you have any concerns about your condition or treatment. We are not responsible or liable, directly or indirectly, for ANY form of damages resulting from the use (or misuse) of information contained in or implied by the information on this site.

How do antacids work to neutralize stomach acid ?

Post author

Any links on this page that lead to products on Amazon and other companies may be affiliate links and we earn a commission if you make a qualifying purchase. Thanks in advance for your support!

How do antacids work to neutralize stomach acid?

Antacids are made up of alkaline constituents. These react with stomach acid – or any acidic substance – turning it into harmless water and salt. If this acid is in your throat or esophagus, the antacid should work quickly to kill the burning pain of reflux.

Find out more below…

Night time reflux? Read how to avoid it here

Do you suffer night time reflux? We may have the answer here

What’s the first thing you do when you feel that chest burn following a hot curry? I guess you reach for the Tums or Rennies?

Antacids are the first weapon of choice against heartburn because they’re readily available and usually in tablet or liquid form.

Their popularity amongst heartburn sufferers is undisputed: In 2015 worldwide sales of antacids were over $10 billion. (Ref 1)

They may also be more affordable than prescription medications.

Perhaps most importantly, though, they are effective. A 2007 study found that over-the-counter medications are effective in treating GERD (Gastro esophageal reflux disease) (Ref 2)

But how do antacids work to neutralize stomach acid? Read more below…

How Do Antacids Work?

Antacids are made up of alkaline constituents. These react with stomach acid – or any acidic substance – turning it into harmless water and salt. If this acid is in your throat or esophagus, the antacid should work quickly to kill the burning pain of reflux.

Slower Working Antacid Medications

In contrast, H2 blockers (histamine H2-receptor antagonists) and Proton Pump Inhibitors (PPI’s) work much more slowly. They reduce the amount of acid produced by the cells in the stomach lining.

Common H2 blockers include

In late 2019, Ranitidine was withdrawn from sale and prescription as a result of concerns over a cancer-linked ingredient. It appears it has been reintroduced,

Commonly prescibed PPI’s, some of which may be available over the counter, include:

What Do Antacids Contain?

There are more than 120 antacid mixtures in the US, containing at least one of the following: Magnesium Hydroxide, Calcium Carbonate, Aluminum Hydroxide and Sodium Bicarbonate.

Calcium Carbonate is an effective antacid which has been used since the first century. Products such as Tums and have calcium carbonate as a principal ingredient.

Antacids that contain calcium carbonate may be longer lasting in their effects than those containing sodium bicarbonate or magnesium.

Aluminum salts dissolve slowly in the stomach, working slowly to relieve heartburn symptoms. They do, however, cause constipation in some people.

Magnesium salts in contrast, act swiftly to neutralize acid but may cause diarrhea.

They are sometimes used together in a product (eg Maalox and Mylanta) in order to cancel out these adverse side effects.

However, there has been some concern about the long-term safety of aluminum. Aluminum may deplete the body of phosphorus and calcium (thereby raising the risk of weak bones) and some products are no longer using it.

Sodium bicarbonate is found in products like Alka-Seltzer and baking soda. It’s fast acting but is a short lived heartburn remedy. Alka Seltzer also contains anhydrous citric acid which in itself is a potent antacid. It is also sold in handy tablet form.

Sodium bicarbonate reacts with stomach acid to produce carbon dioxide gas, resulting in surprising gaseous emissions experienced by users!

Sodium bicarbonate is not generally suitable for people on a salt restricted diet or who have congestive heart failure, high blood pressure or kidney problems. It is not considered safe for pregnant women.

Some antacids contain simethicone (eg Alka-Seltzer Heartburn Plus Gas Relief Chews, and Rennie Deflatine which reduces gas.

Alginate Antacids

Alginate antacids contain alginic acid, and often other antacids mentioned above. Gaviscon for example, contains aluminum hydroxide gel and magnesium carbonate which neutralize stomach acids, as well as alginic acid.

The alginic acid forms a barrier that floats on top of the acid in your stomach, thereby helping to prevent acid moving up into the esophagus.

Since the barrier persists in the stomach for several hours, these types of antacids often provide longer-lasting relief. Indeed, clinical studies have shown Gaviscon is equal to or significantly better than traditional antacids for relieving heartburn symptoms (Ref 3).

Another study showed that Gaviscon® was superior to omeprazole (a PPI) in achieving a 24-h heartburn-free period and is a relevant effective alternative treatment in moderate GERD (Ref 4).

Some of the latest antacids have zinc and copper ingredients; Tummyzen claims these ingredients mean that the benefits last up to 4 times longer.

So, How Do Antacids Work To Neutralize Stomach Acid ?

The process is very simple; the alkali base of the antacid turns the stomach acid, and the reflux in the esophagus, into water and salt.

Contraindications of Antacids

Take antacids as directed by your doctor or by the directions on the package.

Antacids are not recommended if you have any symptoms of appendicitis or bowel inflammation or if you have kidney disease or high blood calcium levels. They may also interact with medications, such as thyroid hormones.

Side effects of antacids may include:

  • Constipation
  • Diarrhea
  • White or pale bowel movements
  • headaches
  • nausea
  • Stomach cramps

Serious side effects can occur with an overuse of antacids, and should not be used long term.

Antacids and acid reducers (H2 Blockers and PPI’s) should not be taken within 1 hour of each another, because the antacid will slow down the effect of the acid reducer.

If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to.

For a night time solution to acid reflux, consider raising the head of your bed, or acquiring a wedge pillow.

Antacids don’t treat the inflammation caused by GERD. It’s important to not self-treat GERD with antacids. This type of medication is only a temporary solution to a long-term problem, assisting with the pain and discomfort of heartburn and acid reflux.

Do visit your doctor if you regularly get heartburn to make sure that there is not a serious cause.


  1. http://www.politifact.com/truth-o-meter/statements/2015/may/03/john-boehner/john-boehner-we-spend-more-money-antacids-we-do-po/
  2. https://www.ncbi.nlm.nih.gov/pubmed/17229239
  3. https://www.ncbi.nlm.nih.gov/pubmed/10848650
  4. https://www.ncbi.nlm.nih.gov/pubmed/22361121

We may earn a commission if you click on the links within this article.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

You cannot copy content of this page