Drug & supplement interaction

Hu Zhang + Acetaminophen, Methocarbamol

Acetaminophen, Methocarbamol brand name: Robaxacet.

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

Acetaminophen, Methocarbamol falls into 2 drug categories that Hu Zhang can interact with; the most serious is rated moderate. Theoretically, hu zhang might increase levels of drugs metabolized by CYP1A2.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Hu Zhang and Acetaminophen, Methocarbamol

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Hu Zhang interacts with whole categories of medication. Acetaminophen, Methocarbamol falls into 2 of those categories, so it can interact with Hu Zhang in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

1 of 2

Why this applies to Acetaminophen, Methocarbamol

Acetaminophen, Methocarbamol falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Hu Zhang interacts with.

Theoretically, hu zhang might increase levels of drugs metabolized by CYP1A2.
Hu zhang contains the constituent resveratrol. In vitro research shows that resveratrol might inhibit the CYP1A2 enzyme. This interaction has not been reported in humans.
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 Robaxacet (acetaminophen plus methocarbamol) and Hu Zhang. This herb is rich in resveratrol, and in test-tube studies resveratrol can slow down a liver enzyme called CYP1A2. Since methocarbamol is partly handled by that enzyme, the idea is that the herb could let a bit more of the drug build up, which might mean more of methocarbamol's usual effects like drowsiness, dizziness, or feeling lightheaded.

But I want to be honest about how soft this is. This is purely theoretical, based on lab data, and it has never actually been reported in people. Neither drug is a prodrug, so the direction (slightly stronger effect) makes sense if anything happens at all. If you take a concentrated Hu Zhang supplement regularly, just give your pharmacist or doctor a heads-up first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Chang, T. K., Chen, J., and Lee, W. B. Differential inhibition and inactivation of human CYP1 enzymes by trans-resveratrol: evidence for mechanism-based inactivation of CYP1A2. J.Pharmacol.Exp.Ther. 2001;299(3):874-882.
Moderate

CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES

2 of 2

Acetaminophen, Methocarbamol also falls under CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES.

Theoretically, hu zhang might increase levels of drugs metabolized by CYP2E1.
Hu zhang contains the constituent resveratrol. In vitro research shows that resveratrol might inhibit the CYP2E1 enzyme. Also, a pharmacokinetic study shows that taking resveratrol 500 mg daily for 10 days prior to taking a single dose of chlorzoxazone 250 mg increases the maximum concentration of chlorzoxazone by about 54%, the area under the curve of chlorzoxazone by about 72%, and the half-life of chlorzoxazone by about 35%. Chlorzoxazone is used as a probe drug for CYP2E1.
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 Robaxacet, which pairs acetaminophen with the muscle relaxant methocarbamol. The acetaminophen part is partly handled by a liver enzyme called CYP2E1. Hu Zhang contains resveratrol, which in lab and one small human study seems to slow this enzyme down. So in theory, your body might clear a bit less acetaminophen, nudging its levels up.

Why does that matter? CYP2E1 is the same pathway that turns some acetaminophen into a byproduct that's hard on the liver, so this gets a little complicated. Honestly, this is theoretical and based mostly on pharmacology, not strong human data with this exact combo. Occasional, label-dose Robaxacet is unlikely to cause a problem, but if you take Hu Zhang regularly, check with 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. Bedada SK, Neerati P. Resveratrol Pretreatment Affects CYP2E1 Activity of Chlorzoxazone in Healthy Human Volunteers. Phytother Res. 2016;30(3):463-8. PubMed

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 Acetaminophen, Methocarbamol one above is among them. If you take anything else, check it against the full list below.

Moderate 825 No known interaction 2,005 (incl. Acetaminophen, Methocarbamol)
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.

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Methocarbamol

This page covers Hu Zhang only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Methocarbamol page lists 158 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Procaine (major) and Siberian Cocklebur (major).

By severity: 6 major · 116 moderate · 36 minor.

From our pharmacist’s overview on the Acetaminophen, Methocarbamol page

“Someone reaching for Robaxacet (acetaminophen with methocarbamol) usually has a sore back and wants relief fast, but this is a combination worth pausing over before adding anything from the supplement shelf. Of the 158 ingredients on file, six carry major ratings, and the sharpest danger is to the liver.”

Reviewed by 2 · Jul 18, 2026

Open the Acetaminophen, Methocarbamol 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 Acetaminophen, Methocarbamol 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 Acetaminophen, Methocarbamol 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%

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

29 days ago today
Medication Acetaminophen, Methocarbamol
Top 25%

#671 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
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 Acetaminophen, Methocarbamol, 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 Acetaminophen, Methocarbamol supplement interactions › Every supplement checked against Acetaminophen, Methocarbamol, ranked by severity 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 Acetaminophen, Methocarbamol Together: Common Questions

Can you take Hu Zhang with Acetaminophen, Methocarbamol?
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.
Why are there 2 interactions listed for Hu Zhang and Acetaminophen, Methocarbamol?
Acetaminophen, Methocarbamol belongs to more than one drug category, and Hu Zhang interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Hu Zhang and Acetaminophen, Methocarbamol 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 Acetaminophen, Methocarbamol 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.