From Licorice to Slippery Elm: What Works for GI Symptoms?

David A. Johnson, MD


November 22, 2019

This transcript has been edited for clarity.

Hello. I'm Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia. Welcome back to another GI Common Concerns.

Alternative or complementary medical therapies, particularly those available over the counter, are increasingly used in the United States. A recent survey suggested that up to 85% of patients with gastrointestinal (GI) symptoms or diseases were using these complementary/alternative medical therapies.

It is very important that we don't blow off patients when they bring up these therapies by saying that there is no evidence to support them or that we've never heard of them. Therefore, I wanted to bring some of these traditional therapies to your attention by discussing a recently published review of their use and, where available, the evidence surrounding it.

Apple Cider Vinegar

Many patients take and swear by apple cider vinegar for reflux disease.

Intuitively, it makes little sense because it's an acetic acid, which can be toxic to the GI system in concentrations greater than 20%. When used for consumption, most vinegars, in particular apple cider vinegar, are diluted down to 5%. When taken as therapies, they are perhaps diluted even more with a little bit of water after a meal.

The evidence on this really is pretty slim. It has been suggested that this works therapeutically by balancing pH. Again, this makes no sense because reflux isn't related to a lack of acid but is due to an excess of acid, potentially in the wrong place.

Although this doesn't make much therapeutic sense, it is something that patients seek out. I always tell them that if they use it and find that it helps, the evidence doesn't really support this, although it hasn't been well studied in trials.


We may underestimate the power of melatonin.

As a supplement, melatonin is traditionally used as a sleep aid. But we also have to remember that the foregut produces melatonin, and the GI tract contains melatonin at levels at least 400 times greater than the pineal gland.

In upper GI disease, melatonin is used for its ability to potentially strengthen the esophageal barrier, although data are very limited on this topic. Some data on the use of melatonin (3 or 6 mg) have suggested that it may be better alone or in conjunction with a proton pump inhibitor (PPI).

Many of our patients with gastroesophageal reflux disease may have nocturnal symptoms, so don't dismiss the appropriate control of their reflux.

I find the argument for melatonin to be inordinately powerful in some of the other GI diseases, in particular inflammatory bowel disease, as it does change some reactivity for colonic mucosa in an animal study.

Although rare, melatonin can cause nightmares, so you should make sure your patients are aware.

Also, most patients don't take melatonin correctly. I ask patients to take it 15-30 minutes before bedtime.

I recommend melatonin quite regularly and see little downside to its use.


One traditional therapy that is more common outside the United States, in particular Japan, is rikkunshito, a product composed of eight different herbal medicines.

A couple of years ago, rikkunshito was the focus of a number of abstracts at Digestive Disease Week, which studied it as a potential remedy in a variety of GI diseases. It has been suggested to have value for non-ulcer dyspepsia and reflux disease in particular. Evidence that it does improve reflux symptoms comes from very limited studies to date conducted primarily in Japan.

Your patients may not be able to get rikkunshito easily unless they order it from overseas, but it's nonetheless something to stay aware of.

Slippery Elm

This botanical product derived from the bark of the slippery elm tree can be formulated in capsules, lozenges, and liquid preparations, including teas. Its constituent carbohydrate becomes viscous in contact with water, and it might offer increased viscosity and potential mucosal protection similar to what we would see with something like sucralfate. However, this has not been well studied for slippery elm.

Slippery elm appears to have only limited data surrounding its therapeutic use. One study[1] assessed its use in a very small cohort of 24 healthy volunteers, who reported a relative perception of having better outcomes of throat soothing. However, this was not a placebo-controlled study.

There is a need to heighten our awareness of this product, as it does increase the rate of miscarriage. This necessitates that it be avoided among women who are or may become pregnant.


Patients may also be trying licorice as an alternative therapy.

It has some potential value in patients with gastric ulcer. Glycyrrhizin is the active component and is something that's been studied, particularly in ulcer healing. However, the clinical utility is limited by the fact that it does have a mineralocorticoid-like activity and therefore may change blood pressure, electrolytes, and a variety of other things.

There has been some investigation into deglycyrrhizinated versions of this product. Deglycyrrhizinated licorice (DGL) has been studied in dyspepsia. The evidence surrounding DGL for reflux disease is very limited.

We have to be aware that licorice is out there and potentially being used by our patients, even though it is not something that we recommend.

Peppermint Oil

One treatment that I think we need to pay special attention to is peppermint oil.

Peppermint oil is a popular treatment for a variety of GI illnesses and has been studied in irritable bowel syndrome. I think peppermint oil as a smooth muscle relaxant has some potential advantage in the upper GI tract, particularly as it relates to noncardiac chest pain and nonobstructive-type dysphagia.

A very recent study looked at using peppermint oil in 38 patients and suggested that it does have a benefit. In this study, 63% of patients with nonobstructive dysphagia with chest pain responded. They took two Altoid-type mints before a meal, whereas those with just chest pain used it on an as-needed basis.

I find that peppermint oil is pretty easy to add in, with very limited downside or risk associated with its use as an alternative therapy. I usually have my patients try some Altoids with a little warm water first so it dissolves easily in their mouth, if they're having noncardiac chest pain.


Acupuncture is obviously well recognized as a traditional Chinese approach to a variety of different medical disorders. It is not something I dismiss. I find that it has some intriguing adjunctive benefits beyond just the acupuncture, via manipulating the needles by adding heat or vibration—almost a kind of TENS [transcutaneous electrical nerve stimulation] type of strategy.

Acupuncture has been studied in noncardiac chest pain and also in reflux disease. The results suggest that it may be an adjunct to decreasing the PPI dose and it may be potentially therapeutic.

We are not sure exactly how it works, though it has been proposed that it does so by promoting changes in visceral hypersensitivity. There has been some research done showing that acupuncture changes the balloon distension pressure in patients with noncardiac chest pain.

Limited Evidence on Use of These Remedies

There has been a lot in the recent literature questioning the established medical therapies we use for GI conditions. These include concerns over the carcinogen potential of the H2-receptor antagonist ranitidine. We've also seen a plague of so-called "fake news" relating to the PPIs and concerns for a variety of adjunctive risks that don't seem to hold up to the rule of evidence.

As a result, more patients may be coming to you to ask about these complementary/alternative therapies, which we need to be aware of. We also need to be frank with our patients about the limited evidence surrounding their use and point out those they may want to avoid entirely, given the potential risks I've outlined. However, we should not be dismissive of things that patients bring to us and instead ask them the right questions.

Hopefully you will find this overview helpful in your next conversations on alternative medical therapies for upper GI disease.

I'm Dr David Johnson. Thanks again for listening, and see you next time.

David A. Johnson, MD, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology. His primary focus is the clinical practice of gastroenterology. He has published extensively in the internal medicine/gastroenterology literature, with principal research interests in esophageal and colon disease, and more recently in sleep and microbiome effects on gastrointestinal health and disease.

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