According to a number of websites, "almost everything you have been told about heartburn, indigestion, and common stomach ailments are lies", and heartburn is actually caused by too little stomach acid.

The truth about most stomach disorders is that they are caused by not having enough acid, so the industry has made fools out of most of us. The true reason behind acid reflux and indigestion is that when the stomach is lacking enough acid, it must churn violently to make the best use of its limited acid during these times of deficiency, which in turn causes pressure and back flows of the existing acid.

Drinking apple cider vinegar is supposed to fix this by adding acid to the stomach.

The science behind the apple cider vinegar cure for heartburn is simple–the stomach uses natural acids to digest food, and apple cider vinegar is very similar in acidity to your stomach acid. Heartburn happens when there is too little acid in the stomach itself to digest your food.

Some people who experience heartburn may not have enough digestive acid.. Apple cider vinegar is acidic in nature and thus it helps. If the sphincter esophagael contains the acid, it closes the LES (lower esophageal sphincter) to protect the esophagus by reflux. And the LES is to open at regular intervals when there is too little acid.

Is there any truth to this? I tried apple cider vinegar once, and not only does it taste and smell terrible, it made my heartburn worse.

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    Be wary of taking apple cider vinegar tablets; they can damage your throat. Hill, L; Woodruff, L; Foote, J; Barretoalcoba, M (2005). "Esophageal Injury by Apple Cider Vinegar Tablets and Subsequent Evaluation of Products". Journal of the American Dietetic Association 105 (7): 1141–4. doi:10.1016/j.jada.2005.04.003. PMID 15983536. I'd certainly recommend talking to your doctor before taking them.
    – Oddthinking
    Commented Jul 4, 2011 at 13:08
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    I wouldn’t try to ingest any acid that comes close in acidity to stomach acid. Did you ever notice how some top models have very bad teeth? This happens when teeth come into contact with stomach acid … Commented Jul 5, 2011 at 9:15
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    Here is what I wonder about this question: Stomach acid has a pH of 1. pH is a logarithmic scale. According to the second link provided above, ACV has a pH of around 2.8-3.0. Also, dosing recommendation is 1 part ACV to 4 parts water. Given all of this: is that small amount of ACV even going to affect the environment of the stomach? There may be something else going on here that I don't understand, but as far as I can see it seems unlikely that the vinegar will have any effect. Commented Jul 6, 2011 at 17:41
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    Also: stomach acid is hydrochloric acid (a strong acid). ACV is acetic acid (a weak acid). It's not as if you are giving your stomach more hydrochloric acid to "help" it digest better. Are these claims assuming that all acids are the same? I'm not understanding this based on the premise alone. Commented Jul 6, 2011 at 17:57
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    @nalgenegirl: Strong vs weak doesn't really matter, since it's already accounted for in the pH. Furthermore, gastric acid is usually diluted to ph 1.3 - 3.0.
    – MSalters
    Commented Jul 7, 2011 at 11:58

2 Answers 2



First, it's wise to define heartburn as gastric reflux, to exclude ischaemic heart disease. The suggested "churning" hypothesis doesn't relate to heart disease at all.

Second, there does exist a feedback mechanism to deal with a lack of gastric acid. That's not (as the vinegar peddlers suggest) mechanical, but simply chemical. Gastric acid is hydrochloric acid, which the body can synthesize from salt and water—you'd be dead before you run out of the building blocks!

A further problem with the vinegar theory is that Histamine (H2) receptor antagonists are FDA approved medicines, from which we can conclude they work better than placebos. The vinegar theory implies that they'd work worse than placebos, because they reduce acidity, not increase it.

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    I wasn't aware there was any other definition of "heartburn"
    – endolith
    Commented Jul 8, 2011 at 3:06
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    The gastrin component of the feedback also stimulates gastric motility so their proposed mechanism does theoretically exist (I very much doubt that theory holds up in practice however). Commented Jul 10, 2011 at 1:28
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    The idea that hydrochloric acid is synthesized with only (table) salt and water is undermined by your link showing that, for example, potassium is involved. I think that point could be safely removed from the answer.
    – Oddthinking
    Commented Nov 19, 2012 at 22:41
  • @Oddthinking: As the link also notes, potassium is recycled. It's a catalyst, not a building block.
    – MSalters
    Commented Nov 20, 2012 at 11:53
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    @endolith: Among of the factors of gastric reflux is increased acidity of stomach acids. Not only that, none of the factors of gastric reflux include reduced acidity of stomach acids. So limiting your ability to produce acid is actually an accepted treatment of gastric reflux.
    – slebetman
    Commented Mar 18, 2016 at 7:50

As another data point, the site CureTogether surveys people on which treatments have been effective for each particular disease. Apple cider vinegar is ranked as the worst treatment for acid reflux:

  • 29% thought it made their reflux worse
  • 43% experienced no effect
  • 28% experienced improvement

For comparison, the highest-ranked treatments are prescription drugs, which improved symptoms for 71% of people.

Also here's a small master's thesis study:

The acid chosen for the study was organic apple cider vinegar with mother. In summary, the results of our study support our second null hypothesis - compared to the placebo trial, the vinegar trials do not show significant alleviation of the heartburn sensation.

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