Drug & supplement interaction

Hibiscus Sabdariffa + Proguanil

Proguanil brand name: Paludrine.

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

Hibiscus Sabdariffa has a minor interaction with Proguanil. Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2C19 substrates.

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

Hibiscus Sabdariffa and Proguanil

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

Minor

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES

Why this applies to Proguanil

Proguanil falls under CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES — the group Hibiscus Sabdariffa interacts with.

Theoretically, Hibiscus sabdariffa extract might reduce the metabolism of CYP2C19 substrates.
In vitro research shows that Hibiscus sabdariffa calyx extract inhibits CYP2C19. 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 something worth knowing about proguanil: it's actually a prodrug. Your body uses an enzyme called CYP2C19 to convert it into its active form, cycloguanil, which is the part that fights off malaria. So this drug depends on that enzyme to do its job.

Lab studies suggest hibiscus extract might slow down CYP2C19. If that happened in real life, your body could make less of the active form, which in theory could make proguanil a little less effective at preventing malaria. I want to be clear, though: this is only seen in test-tube research and has never been reported in actual people. An occasional cup of tart hibiscus tea is very unlikely to matter. If you're relying on proguanil for malaria protection and also use concentrated hibiscus supplements, just mention it to your pharmacist or travel doctor to be safe.

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 Proguanil one above is one of 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. Proguanil)
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 Proguanil

This page covers Hibiscus Sabdariffa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Proguanil page lists 54 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Adrafinil (moderate), Artichoke (moderate), Bacopa (moderate) and Baikal Skullcap (moderate).

By severity: 1 major · 40 moderate · 13 minor.

From our pharmacist’s overview on the Proguanil page

“Malaria prophylaxis leaves little margin for error, so the 54 supplements and herbs on file against proguanil (Paludrine) deserve a careful read rather than a shrug. The single major-rated entry is activated charcoal, which binds medicines in the gut and can cut proguanil exposure enough to undermine your protection.”

Reviewed by 2 · Jul 18, 2026

Open the Proguanil interaction page

How much people look this up

Where Hibiscus Sabdariffa and Proguanil 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 half

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

29 days ago today
Medication Proguanil
Steady interest

#2,474 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 Proguanil, 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 Proguanil supplement interactions › Every supplement checked against Proguanil, 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 Proguanil Together: Common Questions

Can you take Hibiscus Sabdariffa with Proguanil?
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.
How serious is the Hibiscus Sabdariffa and Proguanil 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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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.