Drug & supplement interaction

Rhubarb + Alosetron

Alosetron brand name: Lotronex.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Rhubarb and Alosetron 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 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

Rhubarb and Alosetron

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 Alosetron and Rhubarb 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.

Rhubarb safety at a glance

Rhubarb overall Use caution The stalks are a safe food, but the root used as a laxative can cause cramping and should not be used long-term.
Pregnancy Possibly Unsafe When used in medicinal amounts, rhubarb root is a stimulant laxative; avoid using. Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used in medicinal amounts, rhubarb root is a stimulant laxative; avoid using. 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 Alosetron and Rhubarb? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Alosetron

Interactions in our licensed database are recorded against drug classes, not just single drug names. Alosetron is filed under 3 classifications — serotonergic drugs, serotonergic drugs, oral drugs. Rhubarb has documented interactions with 8 drug classes — the most serious being corticosteroids (moderate), cyclosporine (neoral, sandimmune) (moderate) and digoxin (lanoxin) (moderate) — and none of Alosetron’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

Rhubarb Does Interact With Other Medications

Rhubarb has 658 moderate known drug interactions in our database — Alosetron isn’t one of them. If you take anything else, check it against the full list below.

Moderate 658 No known interaction 2,172 (incl. Alosetron)
Taking anything else?

Check Another of Your Medications Against Rhubarb

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

What to actually watch for

No Interaction Found — But Data Suggests Rhubarb and Alosetron 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.

  • Bloating or gas Additional detail

    Rhubarb

    “Orally, rhubarb can cause cramp-like or spasmodic gastrointestinal discomfort, watery diarrhea, and uterine contractions (18). Rhubarb, alone or in combination with other ingredients, has also been reported to cause bloating, nausea, diarrhea, vomiting, and stomach upset or pain in clinical studies. Diarrhea is more common with a starting dose of at least 3 grams of extract.”

    Rhubarb · Natural Medicines adverse-effect record, reported in cancer.

    6 sources cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    2. 71315. Fan, J. G. Evaluating the efficacy and safety of Danning Pian in the short-term treatment of patients with non-alcoholic fatty liver disease: a multicenter clinical trial. Hepatobiliary.Pancreat.Dis.Int 2004;3(3):375-380.
    3. 71329. Zhang, J. H., Li, L. S., and Zhang, M. Clinical effects of rheum and captopril on preventing progression of chronic renal failure. Chin Med J (Engl.) 1990;103(10):788-793.
    4. 71339. Mitsuma, T., Yokozawa, T., Oura, H., and Terasawa, K. [Rhubarb therapy in patients with chronic renal failure (Part 2)]. Nippon Jinzo Gakkai Shi 1987;29(2):195-207.
    5. 71340. Wu, C. X. [A preliminary study on the effect of a single Rheum officinale in heavy doses in the treatment of acute icteric hepatitis]. Zhong.Xi.Yi.Jie.He.Za Zhi.(Chinese Journal of Modern Developments in Traditional Medicine) 1984;4(2):88-89.
    6. 71341. Jiao, D. H. [Clinical research on the hemostatic effect of rhubarb on peptic ulcer with acute bleeding]. Zhong.Xi.Yi.Jie.He.Za Zhi.(Chinese Journal of Modern Developments in Traditional Medicine) 1984;4(10):597-600, 579.

    Alosetron

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

  • Stomach upset / Diarrhea / Vomiting / Nausea Additional detail

    Rhubarb

    “Orally, rhubarb root and stalk are well tolerated when used in food amounts and seem to be well tolerated when used in medicinal amounts. Rhubarb leaf contains oxalic acid and can be toxic. Topically, rhubarb seems to be well tolerated.

    Most Common Adverse Effects:

    Orally: Cramps, diarrhea, gastrointestinal discomfort, nausea, vomiting.

    Topically: Rash.

    Serious Adverse Effects (Rare):

    Orally: Anaphylaxis.”

    Rhubarb · Natural Medicines adverse-effect record, reported in diarrhea.

    Alosetron

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

  • A skin rash Additional detail

    Rhubarb

    Recorded for Rhubarb in the same Natural Medicines adverse-effect record shown under Stomach upset / Diarrhea / Vomiting / Nausea above.

    Alosetron

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

Reported for Rhubarb but not commonly for Alosetron: kidney problems, a severe allergic reaction, dehydration and swelling.

Effects for Alosetron come from the ADVERSE REACTIONS section of its FDA label; effects for Rhubarb 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

Rhubarb in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Unsafe

When used in medicinal amounts, rhubarb root is a stimulant laxative; avoid using.

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

Overlapping uses

What Alosetron Is Prescribed For, and What Rhubarb Has Been Studied For

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

Alosetron is prescribed for: Alosetron tablets — available as Alosetron, Alosetron Hydrochloride, and Lotronex — are approved only for women with severe diarrhea-predominant irritable bowel syndrome (IBS) whose symptoms have lasted 6 months or longer and who have not gotten adequate relief from conventional therapy. Other causes of GI symptoms must be ruled out first. To qualify as severe, diarrhea-predominant IBS must include diarrhea plus at least one of the following: frequent and severe abdominal pain or discomfort, frequent bowel urgency or fecal incontinence (accidental stool leakage), or significant disruption to daily activities. Clinical studies have not confirmed the same benefit in men.

Rhubarb has been studied for:

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

    Rhubarb for constipation

    It is unclear if rhubarb is beneficial for constipation.

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 Alosetron on your own; if you are taking Rhubarb for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Rhubarb or Alosetron

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Rhubarb or Alosetron, 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 Alosetron

This page covers Rhubarb only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Alosetron 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 Alosetron page

“Alosetron (Lotronex) treats severe diarrhea-predominant IBS by acting on serotonin receptors in the gut, and that is where most of its 38 supplement interactions come from. Twenty of the ingredients, 5-HTP among them, raise serotonin on their own, and stacking them on a serotonin-acting drug is a combination I want you to treat with re…”

Reviewed by 2 · Jul 18, 2026

Open the Alosetron interaction page

One more smart check

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

We hold 133 real supplement products containing Rhubarb, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Rhubarb. Even though Rhubarb itself has no known interaction with Alosetron, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Rhubarb and Alosetron 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 Rhubarb
Top 25%

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

29 days ago today
Medication Alosetron
Top half

#941 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 Rhubarb reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Rhubarb and Alosetron records this page draws on were last updated July 10, 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 Rhubarb

What is Rhubarb?

Rhubarb
  • Constipation
  • Digestive upset
  • Menopausal symptoms
  • Kidney and liver conditions (traditional)
  • Pancreatitis (hospital/traditional use)

Rhubarb root has a long history of use as a laxative and in traditional Chinese medicine, and its edible stalks are a common food. Most medicinal claims are backed by limited or low-quality evidence, and the root can cause cramping and diarrhea. The leaves are toxic and should never be eaten, and rhubarb supplements are best avoided in pregnancy and breastfeeding.

Rheum officinale · Polygonaceae · Root, rhizome, and edible stalk (leaves are toxic and not used) · Dried root powder, capsules, tablets, tinctures, teas, and culinary stalks

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

Rhubarb: dosing

There is no single standardized dose for rhubarb supplements, and the right amount depends on the product and the form. Strengths of capsules, powders, and tinctures vary widely.If you use a commercial product, follow the directions on the label and do not exceed the recommended amount or use it longer than directed.

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

Read the full Rhubarb monograph & all interactions
Medication

About Alosetron

What Is Alosetron Used For?

Brand name: Lotronex

Alosetron tablets — available as Alosetron, Alosetron Hydrochloride, and Lotronex — are approved only for women with severe diarrhea-predominant irritable bowel syndrome (IBS) whose symptoms have lasted 6 months or longer and who have not gotten adequate relief from conventional therapy. Other causes of GI symptoms must be ruled out first.

To qualify as severe, diarrhea-predominant IBS must include diarrhea plus at least one of the following: frequent and severe abdominal pain or discomfort, frequent bowel urgency or fecal incontinence (accidental stool leakage), or significant disruption to daily activities. Clinical studies have not confirmed the same benefit in men.

See full Alosetron drug information
Keep checking

Other Drugs & Rhubarb

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

0Major
658Moderate
0Minor
2,171No known interaction
658 Moderate 2,171 No interaction
Moderate

658 interactions

Showing 60 of 658 moderate interactions — see all 658 on the Rhubarb page.

No interaction 2,171 drugs checked — show the list

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

Showing the 60 most looked-up of 2,171 medications checked with no known interaction — see the full Rhubarb list.

See the full Rhubarb interactions page
See every supplement checked against Alosetron, ranked by severity
Evidence & sources

Rhubarb References

The 20 references that drive our Rhubarb 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. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  4. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  5. Nusko G, Schneider B, Schneider I, et al. Anthranoid laxative use is not a risk factor for colorectal neoplasia: results of a prospective case control study. Gut 2000;46:651-5. PubMed
  6. Kwan TH, Tong MK, Leung KT, et al. Acute renal failure associated with prolonged intake of slimming pills containing anthraquinones. Hong Kong Med J 2006;12:394-7.
  7. Fairbairn JW. The anthraquinone laxatives. Biological assay and its relation to chemical structure. Pharmacology 1976;14:48-61. PubMed
  8. Siegers, C. P., Hertzberg-Lottin, E., Otte, M., and Schneider, B. Anthranoid laxative abuse--a risk for colorectal cancer? Gut 1993;34(8):1099-1101. PubMed
  9. Fan, J. G. Evaluating the efficacy and safety of Danning Pian in the short-term treatment of patients with non-alcoholic fatty liver disease: a multicenter clinical trial. Hepatobiliary.Pancreat.Dis.Int 2004;3(3):375-380.
  10. Yan, M., Zhang, L. Y., Sun, L. X., Jiang, Z. Z., and Xiao, X. H. Nephrotoxicity study of total rhubarb anthraquinones on Sprague Dawley rats using DNA microarrays. J Ethnopharmacol. 4-15-2006; PubMed
  11. Zhang, J. H., Li, L. S., and Zhang, M. Clinical effects of rheum and captopril on preventing progression of chronic renal failure. Chin Med J (Engl.) 1990;103(10):788-793.
  12. Mitsuma, T., Yokozawa, T., Oura, H., and Terasawa, K. [Rhubarb therapy in patients with chronic renal failure (Part 2)]. Nippon Jinzo Gakkai Shi 1987;29(2):195-207.
  13. Wu, C. X. [A preliminary study on the effect of a single Rheum officinale in heavy doses in the treatment of acute icteric hepatitis]. Zhong.Xi.Yi.Jie.He.Za Zhi.(Chinese Journal of Modern Developments in Traditional Medicine) 1984;4(2):88-89.
  14. Jiao, D. H. [Clinical research on the hemostatic effect of rhubarb on peptic ulcer with acute bleeding]. Zhong.Xi.Yi.Jie.He.Za Zhi.(Chinese Journal of Modern Developments in Traditional Medicine) 1984;4(10):597-600, 579.
  15. Jiao, D. H., Ma, Y. H., Chen, S. J., Liu, C. T., Shu, H. N., and Chu, C. M. Resume of 400 cases of acute upper digestive tract bleeding treated by rhubarb alone. Pharmacology 1980;20 Suppl 1:128-130.

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 Rhubarb and Alosetron Together: Common Questions

Is it safe to take Rhubarb with Alosetron?
We do not list a known interaction between Rhubarb and Alosetron. 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 Rhubarb and Alosetron have any of the same side effects?
Yes — our sources link each of them separately to 6 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.
Are Rhubarb and Alosetron 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 Rhubarb in each. That is a conversation for your prescriber, especially if Alosetron is being adjusted to a target.
How was the Rhubarb and Alosetron combination checked?
Interactions in our licensed database are recorded against drug classes. Alosetron is filed under 3 classifications, and Rhubarb has documented interactions with 8 drug classes — none of Alosetron'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 Rhubarb interact with any other medications?
Yes. Rhubarb has 658 documented drug interactions in our database — Alosetron 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 Alosetron interact with any supplements?
Yes. Alosetron has documented interactions with 38 supplements in our database — Rhubarb is not one of them. The Alosetron 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

Rhubarb monograph Uses, safety profile, and every drug interaction in one place Alosetron drug information The full plain-English guide to this medication Alosetron supplement interactions Every supplement checked against Alosetron, 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 20 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Alosetron and Rhubarb?

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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.