Drug & supplement interaction

Hibiscus Sabdariffa + Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine

Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine brand name: Vicks NyQuil.

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

Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine falls into 5 drug categories that Hibiscus Sabdariffa can interact with; the most serious is rated minor. Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP1A2 substrates.

Read the full interaction report
SeverityMinor
LikelihoodPossible
Interactions5
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Hibiscus Sabdariffa and Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine

These two interact in 5 distinct ways. Each one is explained separately below.

Why Are There 5 Interactions?

Hibiscus Sabdariffa interacts with whole categories of medication. Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine falls into 5 of those categories, so it can interact with Hibiscus Sabdariffa in 5 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Minor).

Minor

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES

1 of 5

Why this applies to Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine

Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine falls under CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES — the group Hibiscus Sabdariffa interacts with.

Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP1A2 substrates.
In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP1A2. This interaction has not been reported in humans.
Severity Minor 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 honest picture: this NyQuil combo isn't really a CYP1A2 story. The interaction on file is based only on lab dish research showing hibiscus may block an enzyme called CYP1A2, and it has never actually been seen in people. None of NyQuil's main ingredients (acetaminophen, dextromethorphan, doxylamine, pseudoephedrine) lean heavily on CYP1A2 to be cleared, so any real effect here is very unlikely.

If hibiscus did slow things slightly, you might in theory notice a touch more drowsiness from the doxylamine or dextromethorphan. With a cup of tart hibiscus tea, I wouldn't lose sleep over it. Since hibiscus can also lower blood pressure and pseudoephedrine raises it, just mention both to your pharmacist if you use them often.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Johnson SS, Oyelola FT, Ari T, Juho H. In vitro inhibitory activities of the extract of Hibiscus sabdariffa L. (family Malvaceae) on selected cytochrome P450 isoforms. Afr J Tradit Complement Altern Med. 2013 Apr 12;10(3):533-40.
Minor

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES

2 of 5

Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine also falls under CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES.

Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2D6 substrates.
In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2D6. This interaction has not been reported in humans.
Severity Minor 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

In this NyQuil combo, the ingredient that matters here is dextromethorphan (the cough suppressant). Your body relies on an enzyme called CYP2D6 to clear it. Lab studies suggest concentrated hibiscus extract may slow that enzyme down a little, which could let dextromethorphan linger longer and feel a bit stronger. In practice that might mean more drowsiness, dizziness, or that foggy, sedated feeling.

Honestly, I wouldn't lose sleep over this one. It's only a theoretical concern from test-tube research and hasn't been seen in real people, and a cup of tart hibiscus tea is very different from a concentrated supplement. If you take strong hibiscus capsules regularly, just give your pharmacist a heads-up so they can double-check.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Johnson SS, Oyelola FT, Ari T, Juho H. In vitro inhibitory activities of the extract of Hibiscus sabdariffa L. (family Malvaceae) on selected cytochrome P450 isoforms. Afr J Tradit Complement Altern Med. 2013 Apr 12;10(3):533-40.
Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 5

Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP3A4 substrates.
In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP3A4. This interaction has not been reported in humans.
Severity Minor 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

NyQuil bundles a few ingredients together, and one of them, dextromethorphan (the cough suppressant), is partly handled by a liver enzyme called CYP3A4. In a lab dish, hibiscus extract slowed that enzyme down a bit. In theory, that could let a little more dextromethorphan hang around, which might mean more drowsiness or that foggy, lightheaded feeling some people get from cough medicine.

Here's the honest part: this has only been seen in test tubes, never in real people, and it's rated a minor concern. A cup or two of hibiscus tea is very unlikely to cause any trouble with an occasional dose of NyQuil. If you're using strong hibiscus supplements regularly, just mention it to your pharmacist so they can give you peace of mind.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Johnson SS, Oyelola FT, Ari T, Juho H. In vitro inhibitory activities of the extract of Hibiscus sabdariffa L. (family Malvaceae) on selected cytochrome P450 isoforms. Afr J Tradit Complement Altern Med. 2013 Apr 12;10(3):533-40.
Minor

ACETAMINOPHEN (Tylenol, others)

4 of 5
Theoretically, taking Hibiscus sabdariffa with acetaminophen might decrease the clinical effects of acetaminophen.
There is some evidence that consuming a Hibiscus sabdariffa beverage (Zobo drink) before taking acetaminophen can decrease the elimination half-life of acetaminophen. Hibiscus sabdariffa does not seem to decrease maximum concentration or area under the curve of acetaminophen. The clinical significance of this is unknown.
Severity Minor Likelihood Probable Evidence B

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..

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

Here's the gist for your NyQuil, which is a combo product. The interaction on file is really about just one of its ingredients: the acetaminophen (the pain and fever reducer). Some early research found that drinking hibiscus (sometimes called a Zobo drink) before taking acetaminophen made the body clear the acetaminophen a little faster. In plain terms, the medicine may not hang around quite as long, so theoretically you might get slightly less fever or pain relief from that part of NyQuil.

Honestly, this is a minor and not well-proven effect, and the researchers themselves said the real-world impact is unknown. Casual hibiscus tea is unlikely to matter much. The other ingredients (dextromethorphan, doxylamine, pseudoephedrine) aren't part of this interaction. If you use hibiscus regularly or in supplement form, just run it by your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Kolawole JA, Maduenyi A. Effect of zobo drink (Hibiscus sabdariffa water extract) on pharmacokinetics of acetaminophen in human volunteers. Eur J Drug Metab Pharmacokinet 2004;29:25-9.
Minor

CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES

5 of 5

Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine also falls under CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES.

Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2E1 substrates.
In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2E1. This interaction has not been reported in humans.
Severity Minor 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 short version: in NyQuil, the ingredient that matters most for this one is the acetaminophen (Tylenol). A liver enzyme called CYP2E1 helps process acetaminophen, and lab dish studies suggest hibiscus may slow that enzyme down a bit. In theory, that could let a little more acetaminophen hang around. The reassuring part is that this is only a test-tube finding and has never actually been reported in real people, so I wouldn't lose sleep over it.

A cup or two of hibiscus tea is very unlikely to cause trouble. The bigger, more practical point with NyQuil is simply not doubling up on acetaminophen from other products. If you regularly use concentrated hibiscus supplements, just mention it to your pharmacist.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Johnson SS, Oyelola FT, Ari T, Juho H. In vitro inhibitory activities of the extract of Hibiscus sabdariffa L. (family Malvaceae) on selected cytochrome P450 isoforms. Afr J Tradit Complement Altern Med. 2013 Apr 12;10(3):533-40.

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

Hibiscus Sabdariffa Also Interacts With Other Medications

Hibiscus Sabdariffa has 2 major, 266 moderate, 818 minor known drug interactions in our database — the Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine one above is among them. If you take anything else, check it against the full list below.

Major 2 Moderate 266 Minor 818 No known interaction 1,744 (incl. Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine)
Taking anything else?

Check Another of Your Medications Against Hibiscus Sabdariffa

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

Everything else you take

See Every Supplement That Interacts With Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine

This page covers Hibiscus Sabdariffa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine page lists 286 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), Ephedra (major) and Grapefruit (major).

By severity: 14 major · 227 moderate · 45 minor.

Open the Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine interaction page

How much people look this up

Where Hibiscus Sabdariffa and Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine 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 Hibiscus Sabdariffa
Top 25%

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

29 days ago today
Medication Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine
Top 25%

#543 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 Hibiscus Sabdariffa

What is Hibiscus Sabdariffa?

Hibiscus Sabdariffa
  • High blood pressure
  • Heart and cholesterol health
  • Digestive upset
  • Antioxidant support
  • Fever and general wellness

Hibiscus sabdariffa is a tart, cranberry-flavored plant most often consumed as a tea, and its best-studied use is for mildly lowering blood pressure. Evidence for other uses is limited, and while hibiscus tea is generally well tolerated in food amounts, concentrated supplements should be used cautiously and avoided in pregnancy. Talk to your pharmacist or doctor before using it for a medical condition.

Read the full Hibiscus Sabdariffa monograph & all interactions
Keep checking

Other Drugs & Hibiscus Sabdariffa

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

2Major
266Moderate
818Minor
1,743No known interaction
2 Major 266 Moderate 818 Minor 1,743 No interaction
Major

2 interactions

Moderate

266 interactions

Showing 60 of 266 moderate interactions — see all 266 on the Hibiscus Sabdariffa page.

Minor

818 interactions

Showing 60 of 818 minor interactions — see all 818 on the Hibiscus Sabdariffa page.

No interaction 1,743 drugs checked — show the list

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

Showing the 60 most looked-up of 1,743 medications checked with no known interaction — see the full Hibiscus Sabdariffa list.

See the full Hibiscus Sabdariffa interactions page
See every supplement checked against Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine, 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
Hibiscus Sabdariffa monograph › Uses, safety, and every drug interaction in one place Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine supplement interactions › Every supplement checked against Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine, 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 Hibiscus Sabdariffa and Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine Together: Common Questions

Can you take Hibiscus Sabdariffa with Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 5 interactions listed for Hibiscus Sabdariffa and Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine?
Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine belongs to more than one drug category, and Hibiscus Sabdariffa 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 Hibiscus Sabdariffa and Acetaminophen, Dextromethorphan, Doxylamine, Pseudoephedrine interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

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