Drug & supplement interaction

Hu Zhang + Dextromethorphan

Dextromethorphan brand names: Hold, Benylin Adult, Benylin Pediatric, Theraflu Thin Strips Long Acting Cough, Neo Citran Thin Strips Cough.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Hu Zhang has a moderate interaction with Dextromethorphan. Theoretically, hu zhang might increase levels of drugs metabolized by CYP3A4.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Hu Zhang and Dextromethorphan

Here is the interaction we found between these two, with the evidence behind it.

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Dextromethorphan

Dextromethorphan falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Hu Zhang interacts with.

Theoretically, hu zhang might increase levels of drugs metabolized by CYP3A4.
Hu zhang contains the constituent resveratrol. In vitro research shows that resveratrol might inhibit the CYP3A4 enzyme. However, a clinical study in adults with NAFLD found that adding resveratrol 3000 mg daily for 8 weeks did not necessitate dose adjustments to any established medications metabolized by CYP3A4.
Severity Moderate Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist with Hu Zhang and your cough medicine. Hu Zhang is loaded with resveratrol, and in test-tube studies resveratrol can slow down an enzyme called CYP3A4. Since dextromethorphan is partly cleared by that enzyme, the idea is that the herb could let a bit more of the drug linger in your system. If that happened, you might feel more of dextromethorphan's usual effects, like drowsiness, dizziness, or feeling foggy or queasy.

I want to be honest about how shaky this concern is. It's theoretical, based on lab data, and one human study using a big resveratrol dose didn't require any medication changes. For most people taking dextromethorphan short term, this likely won't cause trouble. Still, if you use Hu Zhang regularly, mention it to your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Piver B, Berthou F, Dreano Y, Lucas D. Inhibition of CYP3A, CYP1A and CYP2E1 activities by resveratrol and other non volatile red wine components. Toxicol Lett 2001;125:83-91. PubMed
  2. Yu, C., Shin, Y. G., Kosmeder, J. W., Pezzuto, J. M., and van Breemen, R. B. Liquid chromatography/tandem mass spectrometric determination of inhibition of human cytochrome P450 isozymes by resveratrol and resveratrol-3-sulfate. Rapid Commun.Mass Spectro PubMed
  3. Chachay VS, Macdonald GA, Martin JH, Whitehead JP, O'Moore-Sullivan TM, Lee P, Franklin M, Klein K, Taylor PJ, Ferguson M, Coombes JS, Thomas GP, Cowin GJ, Kirkpatrick CM, Prins JB, Hickman IJ. Resveratrol does not benefit patients with nonalcoholic fatty

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction 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.
  • PossibleInteraction 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.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Hu Zhang Also Interacts With Other Medications

Hu Zhang has 825 moderate known drug interactions in our database — the Dextromethorphan one above is one of them. If you take anything else, check it against the full list below.

Moderate 825 No known interaction 2,005 (incl. Dextromethorphan)
Taking anything else?

Check Another of Your Medications Against Hu Zhang

Covers the 2,830 medications we’ve checked against Hu Zhang. Pick one to open its full report.

From our Q&A

Questions About Hu Zhang or Dextromethorphan

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Hu Zhang or Dextromethorphan, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Dextromethorphan

This page covers Hu Zhang only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Dextromethorphan page lists 171 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Lithium (major), St. John's Wort (major) and 1,3-dmaa (moderate).

By severity: 4 major · 125 moderate · 42 minor.

From our pharmacist’s overview on the Dextromethorphan page

“A glass of grapefruit juice can push dextromethorphan (Benylin, Hold, and other cough medicines) to higher levels than intended, one of four major-rated entries among the 171 supplements and herbs on file, and the list as a whole warrants real care. Most interactions trace back to the liver enzymes (CYP3A4 and CYP2D6) that clear dextro…”

Reviewed by 2 · Jul 18, 2026

Open the Dextromethorphan interaction page

One more smart check

Taking Hu Zhang as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,014 real supplement products containing Hu Zhang, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Hu Zhang. Your product may carry other ingredients that interact with Dextromethorphan too, on top of Hu Zhang — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Hu Zhang and Dextromethorphan Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Hu Zhang
Top 25%

#238 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Dextromethorphan
Top 5%

#80 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Supplement

About Hu Zhang

What is Hu Zhang?

  • Source of resveratrol
  • Heart and circulation support
  • Inflammation
  • Liver and digestive complaints (traditional)
  • Cough and respiratory symptoms (traditional)
  • Skin and joint conditions (traditional topical use)

Hu Zhang (Japanese knotweed root) is a traditional Chinese herb that is one of the richest natural sources of resveratrol and emodin. Some lab and early human research looks interesting for inflammation and heart health, but high-quality evidence in people is limited. Talk to your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Read the full Hu Zhang monograph & all interactions
Medication

About Dextromethorphan

What Is Dextromethorphan Used For?

Brand names: Hold, Benylin Adult, Benylin Pediatric, Theraflu Thin Strips Long Acting Cough, Neo Citran Thin Strips Cough

Dextromethorphan temporarily relieves cough due to minor throat and bronchial irritation, such as the kind that comes with the common cold or breathing in irritants. It also helps reduce the urge to cough so you — or your child — can get to sleep.

Some products, including CVS Long Acting Cough and Premier Value Tussin Cough oral liquids, are also indicated to help loosen phlegm (mucus) and thin bronchial secretions to help drain the airways.

See full Dextromethorphan drug information
Keep checking

Other Drugs & Hu Zhang

Browse every other medication we’ve checked against Hu Zhang — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
825Moderate
0Minor
2,004No known interaction
825 Moderate 2,004 No interaction
Moderate

825 interactions

Showing 60 of 825 moderate interactions — see all 825 on the Hu Zhang page.

No interaction 2,004 drugs checked — show the list

We also checked Hu Zhang against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,004 medications checked with no known interaction — see the full Hu Zhang list.

See the full Hu Zhang interactions page
See every supplement checked against Dextromethorphan, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Hu Zhang monograph › Uses, safety, and every drug interaction in one place Dextromethorphan supplement interactions › Every supplement checked against Dextromethorphan, ranked by severity Dextromethorphan drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Hu Zhang and Dextromethorphan Together: Common Questions

Can you take Hu Zhang with Dextromethorphan?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Hu Zhang and Dextromethorphan interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Dextromethorphan and Hu Zhang?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.