Herb & supplement monograph

Barley Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Barley interacts with medications. The heart of this page is the interaction list — every drug Barley is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Barley is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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On this page

Barley Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Barley drug interaction appears low for most people. Only a single interaction is on record, it is rated moderate rather than major, and it rests on animal research alone.

Interactions deserving the most attention

The one combination worth knowing about involves triclabendazole, a medicine used to treat liver fluke infections. Animal studies suggest that a diet rich in barley may reduce how much of this drug the body absorbs, which could in theory make the treatment less effective. This effect has not been shown in people, so we view it as a precaution rather than a proven problem, but it is sensible for anyone taking this medicine to be aware of it.

What the rest of the list means

Because barley is a common food grain, it is reassuring that this is the only flagged interaction, and even that one is theoretical at this point. A predicted effect seen only in animals often does not translate into a meaningful change in humans, and no human evidence of harm has been reported here.

Check your medications against Barley

Based on HelloPharmacist’s Barley interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Barley

1 medication has a known interaction with Barley, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Barley using our pharmacist-reviewed interaction data.

AI summaries are generated from our Barley interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Barley combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Barley affects

Every type of medication (drug category) Barley is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 1 drug category Barley interacts with

Triclabendazole (egaten)

Triclabendazole (Egaten)

Theoretically, barley might decrease the clinical effects of triclabendazole.
Animal research suggests that a diet supplemented with barley can reduce the bioavailability of triclabendazole when taken concomitantly. This effect has not been shown in humans.

Likelihood Possible Evidence D

Monograph

Barley: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Barley is a nutritious whole grain that is a good source of soluble fiber called beta-glucan, which has solid evidence for modestly lowering LDL ('bad') cholesterol when eaten regularly. It is safe as a food for most people, but those with celiac disease or gluten sensitivity should avoid it since it contains gluten. Talk to your pharmacist or doctor before using concentrated barley supplements, especially if you have a health condition.

Scientific name: Hordeum vulgare
Family: Poaceae
Part used: Grain (seed), and sometimes young leaves/grass and bran
Common forms: Whole grain, flour, flakes, barley bran, beta-glucan supplements, barley grass powder, tea, and capsules

People commonly use it for

High cholesterol
Heart health support
Blood sugar support
Digestive regularity and fiber
General nutrition

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallLikely safe

Barley is safe for most people when eaten as a normal food, but it contains gluten.

PregnancyLikely Safe

When used orally in amounts commonly found in foods.

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

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Overview

Barley (Hordeum vulgare) is one of the world's oldest cultivated grains. It grows as a grassy cereal plant and is harvested for its seed-like grains. Barley is grown all over the world and is used as food for people and animals, and to make malt for beer and whiskey.

As a food, barley comes in several forms, including hulled barley, pearl (pearled) barley, barley flakes, and barley flour. It is also a popular source of soluble fiber called beta-glucan. Some people take barley grass powder or beta-glucan supplements for added health benefits.

How it works

The main active ingredient in barley is beta-glucan, a type of soluble fiber. In the gut, beta-glucan forms a thick, gel-like substance. This gel is thought to trap some cholesterol and bile acids so they are carried out of the body instead of absorbed, which can lower blood cholesterol over time.

The same gel-forming effect can slow digestion and the rise in blood sugar after meals. Barley also contains antioxidants such as tocopherols and tocotrienols (forms of vitamin E), and compounds like hordenine and lunasin that are being studied. Much of the research on these specific compounds is still early and comes from laboratory or animal studies.

Effectiveness

Does Barley work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 11 uses evaluated

2 Likely effective 1 Leans ineffective 8 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Likely Effective Coronary heart disease (CHD)