Drug & supplement interaction

Hibiscus Sabdariffa + Granisetron

Granisetron brand names: Kytril, Sustol.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Hibiscus Sabdariffa and Granisetron in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Granisetron states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Hibiscus Sabdariffa and Granisetron

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Granisetron and Hibiscus Sabdariffa in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Hibiscus Sabdariffa safety at a glance

Hibiscus Sabdariff... overall Use caution Generally well tolerated as a tea, but concentrated extracts and high doses warrant caution.
Pregnancy Possibly Unsafe When used orally. Hibiscus sabdariffa is thought to be a menstrual stimulant, and might have abortifacient effects. Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used orally in large amounts. Animal research found that administering large doses of Hibiscus sabdariffa during lactation decreases food and water intake... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Granisetron and Hibiscus Sabdariffa? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Granisetron

Interactions in our licensed database are recorded against drug classes, not just single drug names. Granisetron is filed under 3 classifications — serotonergic drugs, serotonergic drugs, oral drugs. Hibiscus Sabdariffa has documented interactions with 16 drug classes — the most serious being chloroquine (aralen) (major), antidiabetes drugs (moderate) and antihypertensive drugs (moderate) — and none of Granisetron’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Hibiscus Sabdariffa Does Interact With Other Medications

Hibiscus Sabdariffa has 2 major, 266 moderate, 819 minor known drug interactions in our database — Granisetron isn’t one of them. If you take anything else, check it against the full list below.

Major 2 Moderate 266 Minor 819 No known interaction 1,743 (incl. Granisetron)
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.

What to actually watch for

No Interaction Found — But Data Suggests Hibiscus Sabdariffa and Granisetron May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Constipation / Stomach pain / Nausea Additional detail

    Hibiscus Sabdariffa

    “Orally, taking a specific Hibiscus sabdariffa leaf extract (Green Chem) 1 gram daily has been associated with reports of transient gastrointestinal symptoms such as abdominal distention, flatulence, and epigastric pain in one clinical trial. However, the overall rate of these adverse effects was similar to placebo.”

    Hibiscus Sabdariffa · Natural Medicines adverse-effect record, reported in constipation.

    4 sources cited
    1. 17415. Kuriyan R, Kumar DR, Rajendran R, Kurpad AV. An evaluation of the hypolipidemic effect of an extract of Hibiscus Sabdariffa leaves in hyperlipidemic Indians: a double blind, placebo controlled trial. BMC Complement Altern Med 2010;10:27. PubMed
    2. 55000. Hernandez-Perez, F. and Herrera-Arellano, A. [Therapeutic use Hibiscus sabadariffa extract in the treatment of hypercholesterolemia. A randomized clinical trial]. Rev.Med Inst.Mex.Seguro.Soc. 2011;49(5):469-480.
    3. 93816. Sabzghabaee AM, Ataei E, Kelishadi R, Ghannadi A, Soltani R, Badri S, Shirani S. Effect of Hibiscus sabdariffa Calices on Dyslipidemia in Obese Adolescents: A Triple-masked Randomized Controlled Trial. Mater Sociomed. 2013;25(2):76-9. PubMed
    4. 101733. Al-Anbaki M, Nogueira RC, Cavin AL, et al. Treating uncontrolled hypertension with Hibiscus sabdariffa when standard treatment is insufficient: Pilot intervention. J Altern Complement Med. 2019;25(12):1200-1205.

    Granisetron

    Listed in the ADVERSE REACTIONS section of the FDA label for Granisetron. Read the label on DailyMed ›

  • Headache Additional detail

    Hibiscus Sabdariffa

    “Orally, taking Hibiscus sabdariffa calyx extract 3 grams daily has been associated with one report of tremor and headache in one clinical trial.”

    Hibiscus Sabdariffa · Natural Medicines adverse-effect record, reported in cluster headache.

    1 source cited
    1. 55000. Hernandez-Perez, F. and Herrera-Arellano, A. [Therapeutic use Hibiscus sabadariffa extract in the treatment of hypercholesterolemia. A randomized clinical trial]. Rev.Med Inst.Mex.Seguro.Soc. 2011;49(5):469-480.

    Granisetron

    Listed in the ADVERSE REACTIONS section of the FDA label for Granisetron. Read the label on DailyMed ›

Reported for Hibiscus Sabdariffa but not commonly for Granisetron: bloating or gas, ringing in the ears and tremor or shakiness.

Effects for Granisetron come from the ADVERSE REACTIONS section of its FDA label; effects for Hibiscus Sabdariffa come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Hibiscus Sabdariffa in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When used orally. Hibiscus sabdariffa is thought to be a menstrual stimulant, and might have abortifacient effects.

Lactation Possibly Unsafe

When used orally in large amounts. Animal research found that administering large doses of Hibiscus sabdariffa during lactation decreases food and water intake during pregnancy and delays puberty in offspring; however, this has not been assessed in humans.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

How to take them

Some Granisetron Products Have a Food Rule — Hibiscus Sabdariffa Should Not Break It

At least one FDA label for a product containing Granisetron says to take it on an empty stomach. Most supplements — Hibiscus Sabdariffa included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Granisetron on its own and move Hibiscus Sabdariffa to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Granisetron products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

Recommended Dosage ( 2.2 ): The recommended dosage in adults is 10 mg administered as a single subcutaneous injection at least 30 minutes before the start of emetogenic chemotherapy on Day 1.

From the Dosage and Administration section of the FDA label we read for Granisetron — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Overlapping uses

What Granisetron Is Prescribed For, and What Hibiscus Sabdariffa Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Granisetron is a prescription medicine with approved uses on its FDA label. Hibiscus Sabdariffa is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Granisetron is prescribed for: Granisetron is used to prevent nausea and vomiting linked to emetogenic (nausea-causing) cancer chemotherapy — including high-dose cisplatin — and radiation therapy, including total body irradiation and fractionated abdominal radiation. Granisetron hydrochloride tablets and Granisol oral solution are approved for both the chemotherapy and radiation indications. Sancuso skin patch is approved for prevention of nausea and vomiting in adults receiving moderately and/or highly emetogenic chemotherapy regimens of up to 5 consecutive days. Granisetron hydrochloride injection (intravenous) is also used to prevent and treat postoperative nausea and vomiting in adults.

Read the rest of what Granisetron is prescribed for

Sustol (subcutaneous injection) is used in combination with other anti-nausea medicines in adults specifically for the prevention of acute and delayed nausea and vomiting associated with moderately emetogenic chemotherapy or anthracycline and cyclophosphamide combination chemotherapy regimens.

Hibiscus Sabdariffa has been studied for:

  • Cancer studied, not established Hibiscus Sabdariffa has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Hibiscus Sabdariffa for cancer

    Although there has been interest in using oral Hibiscus sabdariffa for cancer, there is insufficient reliable information about the clinical effects of Hibiscus sabdariffa for this condition.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Granisetron on your own; if you are taking Hibiscus Sabdariffa for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

Everything else you take

See Every Supplement That Interacts With Granisetron

This page covers Hibiscus Sabdariffa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Granisetron page lists 38 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Lithium (major), 5-htp (moderate), Acetyl-l-carnitine (moderate) and Ayahuasca (moderate).

By severity: 2 major · 25 moderate · 11 minor.

From our pharmacist’s overview on the Granisetron page

“Granisetron (Kytril, Sustol) blocks serotonin signals to stop nausea from chemotherapy and surgery, and this is a list that warrants real caution before you add a supplement to it. Most of the entries raise serotonin themselves, and stacking them on a serotonin-acting drug can push toward serotonin syndrome, a dangerous overload of tha…”

Reviewed by 2 · Jul 18, 2026

Open the Granisetron interaction page

How much people look this up

Where Hibiscus Sabdariffa and Granisetron 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

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

29 days ago today
Medication Granisetron
Steady interest

#1,988 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.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Hibiscus Sabdariffa reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Hibiscus Sabdariffa and Granisetron records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
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.

Hibiscus sabdariffa · Malvaceae · Dried flowers (calyces), and sometimes leaves · Tea, dried calyces, capsules, extracts, juices/beverages

An interaction check asks whether these two react with each other — it does not ask whether Hibiscus Sabdariffa is a good idea for someone in your situation. Here is what our Hibiscus Sabdariffa record says about it on its own.

Hibiscus Sabdariffa: dosing

There is no official standardized dose for hibiscus. In studies, people have used it as a tea made from dried calyces or as standardized extracts, but the amounts vary widely between products and studies.If you use a supplement, follow the directions on the product label.

From our Hibiscus Sabdariffa monograph — the full record covers uses, side effects and every documented interaction.

Read the full Hibiscus Sabdariffa monograph & all interactions
Medication

About Granisetron

What Is Granisetron Used For?

Brand names: Kytril, Sustol

Granisetron is used to prevent nausea and vomiting linked to emetogenic (nausea-causing) cancer chemotherapy — including high-dose cisplatin — and radiation therapy, including total body irradiation and fractionated abdominal radiation. Granisetron hydrochloride tablets and Granisol oral solution are approved for both the chemotherapy and radiation indications. Sancuso skin patch is approved for prevention of nausea and vomiting in adults receiving moderately and/or highly emetogenic chemotherapy regimens of up to 5 consecutive days.

Granisetron hydrochloride injection (intravenous) is also used to prevent and treat postoperative nausea and vomiting in adults. Sustol (subcutaneous injection) is used in combination with other anti-nausea medicines in adults specifically for the prevention of acute and delayed nausea and vomiting associated with moderately emetogenic chemotherapy or anthracycline and cyclophosphamide combination chemotherapy regimens.

See full Granisetron drug information
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
819Minor
1,742No known interaction
2 Major 266 Moderate 819 Minor 1,742 No interaction
Major

2 interactions

Moderate

266 interactions

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

Minor

819 interactions

Showing 60 of 819 minor interactions — see all 819 on the Hibiscus Sabdariffa page.

No interaction 1,742 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 1,742 medications checked with no known interaction — see the full Hibiscus Sabdariffa list.

See the full Hibiscus Sabdariffa interactions page
See every supplement checked against Granisetron, ranked by severity
Evidence & sources

Hibiscus Sabdariffa References

The 19 references that drive our Hibiscus Sabdariffa monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  2. 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.
  3. McKay DL, Chen CY, Saltzman E, Blumberg JB. Hibiscus Sabdariffa L. tea (tisane) lowers blood pressure in prehypertensive and mildly hypertensive adults. J Nutr 2010;140:298-303. PubMed
  4. Kuriyan R, Kumar DR, Rajendran R, Kurpad AV. An evaluation of the hypolipidemic effect of an extract of Hibiscus Sabdariffa leaves in hyperlipidemic Indians: a double blind, placebo controlled trial. BMC Complement Altern Med 2010;10:27. PubMed
  5. Haji, Faraji M. and Haji, Tarkhani A. The effect of sour tea (Hibiscus sabdariffa) on essential hypertension. J.Ethnopharmacol. 1999;65(3):231-236. PubMed
  6. Mozaffari-Khosravi, H., Jalali-Khanabadi, B. A., Afkhami-Ardekani, M., Fatehi, F., and Noori-Shadkam, M. The effects of sour tea (Hibiscus sabdariffa) on hypertension in patients with type II diabetes. J Hum.Hypertens 2009;23(1):48-54. PubMed
  7. Gurrola-Diaz, C. M., Garcia-Lopez, P. M., Sanchez-Enriquez, S., Troyo-Sanroman, R., Andrade-Gonzalez, I., and Gomez-Leyva, J. F. Effects of Hibiscus sabdariffa extract powder and preventive treatment (diet) on the lipid profiles of patients with metaboli
  8. Hernandez-Perez, F. and Herrera-Arellano, A. [Therapeutic use Hibiscus sabadariffa extract in the treatment of hypercholesterolemia. A randomized clinical trial]. Rev.Med Inst.Mex.Seguro.Soc. 2011;49(5):469-480.
  9. Mahmoud, B. M., Ali, H. M., Homeida, M. M., and Bennett, J. L. Significant reduction in chloroquine bioavailability following coadministration with the Sudanese beverages Aradaib, Karkadi and Lemon. J.Antimicrob.Chemother. 1994;33(5):1005-1009.
  10. Iyare EE, Adegoke OA. Maternal consumption of an aqueous extract of Hibiscus sabdariffa during lactation accelerates postnatal weight and delays onset of puberty in female offspring. Niger J Physiol Sci. 2008 Jun-Dec;23(1-2):89-94. PubMed
  11. 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.
  12. Sabzghabaee AM, Ataei E, Kelishadi R, Ghannadi A, Soltani R, Badri S, Shirani S. Effect of Hibiscus sabdariffa Calices on Dyslipidemia in Obese Adolescents: A Triple-masked Randomized Controlled Trial. Mater Sociomed. 2013;25(2):76-9. PubMed
  13. Showande SJ, Adegbolagun OM, Igbinoba SI, Fakeye TO. In vivo pharmacodynamic and pharmacokinetic interactions of Hibiscus sabdariffa calyces extracts with simvastatin. J Clin Pharm Ther. 2017;42(6):695-703.
  14. Fakeye TO, Adegoke AO, Omoyeni OC, Famakinde AA. Effects of water extract of Hibiscus sabdariffa, Linn (Malvaceae) 'Roselle' on excretion of a diclofenac formulation. Phytother Res. 2007;21(1):96-8.
  15. Al-Anbaki M, Nogueira RC, Cavin AL, et al. Treating uncontrolled hypertension with Hibiscus sabdariffa when standard treatment is insufficient: Pilot intervention. J Altern Complement Med. 2019;25(12):1200-1205.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Hibiscus Sabdariffa and Granisetron Together: Common Questions

Is it safe to take Hibiscus Sabdariffa with Granisetron?
We do not list a known interaction between Hibiscus Sabdariffa and Granisetron. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Hibiscus Sabdariffa and Granisetron have any of the same side effects?
Yes — our sources link each of them separately to 4 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Hibiscus Sabdariffa and Granisetron at the same time of day?
At least one FDA label for a product containing Granisetron says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Granisetron on its own and move Hibiscus Sabdariffa to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
Are Hibiscus Sabdariffa and Granisetron used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Hibiscus Sabdariffa in each. That is a conversation for your prescriber, especially if Granisetron is being adjusted to a target.
How was the Hibiscus Sabdariffa and Granisetron combination checked?
Interactions in our licensed database are recorded against drug classes. Granisetron is filed under 3 classifications, and Hibiscus Sabdariffa has documented interactions with 16 drug classes — none of Granisetron's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Hibiscus Sabdariffa interact with any other medications?
Yes. Hibiscus Sabdariffa has 1,087 documented drug interactions in our database — Granisetron is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Granisetron interact with any supplements?
Yes. Granisetron has documented interactions with 38 supplements in our database — Hibiscus Sabdariffa is not one of them. The Granisetron interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Hibiscus Sabdariffa monograph Uses, safety profile, and every drug interaction in one place Granisetron drug information The full plain-English guide to this medication Granisetron supplement interactions Every supplement checked against Granisetron, 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 References The 19 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Granisetron and Hibiscus Sabdariffa?

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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.