Drug & supplement interaction

Rhubarb + Tasimelteon

Tasimelteon brand names: Hetlioz, Hetlioz Lq.

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 Tasimelteon 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 Tasimelteon states a food rule worth keeping to.

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Interaction report

Rhubarb and Tasimelteon

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 Tasimelteon 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 Tasimelteon and Rhubarb? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Tasimelteon

Interactions in our licensed database are recorded against drug classes, not just single drug names. Tasimelteon is filed under 5 classifications — including cytochrome p450 1a2 (cyp1a2) substrates, cytochrome p450 1a2 (cyp1a2) substrates, cns depressants. 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 Tasimelteon’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 — Tasimelteon 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. Tasimelteon)
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

What Rhubarb Itself Has Been Linked To

This is not an interaction — nothing below involves Tasimelteon. It is the side-effect record for Rhubarb on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Rhubarb, this list is the first place to look. 2 entries are worth acting on rather than waiting out — marked below.

  • Dehydration / Kidney problems Worth acting on Additional detail

    “Orally, chronic use or abuse of rhubarb can cause electrolyte loss (especially potassium), albuminuria, hematuria, dehydration, and nephropathies (12). There is one case report of renal failure in a patient who took a product containing rhubarb for six weeks. The patient presented with renal failure two days after starting diclofenac, which is known to have nephrotoxic effects.”

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

    2 sources cited
    1. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
    2. 15257. 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.
  • A severe allergic reaction Worth acting on Additional detail

    “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.

  • Bloating or gas Additional detail

    “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.
  • Stomach upset / Diarrhea / Vomiting / Nausea Additional detail

    Recorded for Rhubarb in the same Natural Medicines adverse-effect record shown under A severe allergic reaction above.

  • Swelling Additional detail

    “Orally, chronic use or abuse of rhubarb can cause electrolyte loss (especially potassium), hyperaldosteronism, albuminuria, and edema (12).”

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

    1 source cited
    1. 12. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  • A skin rash Additional detail

    Recorded for Rhubarb in the same Natural Medicines adverse-effect record shown under A severe allergic reaction above.

Everything above comes from the Natural Medicines adverse-effect record for Rhubarb — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Tasimelteon’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Tasimelteon column appears here.

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

How to take them

Some Tasimelteon Products Have a Food Rule — Rhubarb Should Not Break It

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

2 DOSAGE AND ADMINISTRATION Indicated Population Dosage Form Body Weight Recommended Dosage Non-24 ( 2.2 ) Adults Capsules Not applicable 20 mg one hour prior to bedtime Nighttime sleep disturbances in SMS ( 2.3 ) Patients 16 years of age and older Capsules Not applicable 20 mg one hour prior to bedtime Pediatric Patients 3 to 15 years of age Oral Suspension ≤ 28 kg 0.7 mg/kg one hour before bedti

From the Dosage and Administration section of the FDA label we read for Tasimelteon — where that label names a specific product, the instruction is that product's. See the Tasimelteon drug page ›

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.

From our Q&A

Questions About Rhubarb or Tasimelteon

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 Tasimelteon, 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 Tasimelteon

This page covers Rhubarb only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tasimelteon page lists 218 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Grapefruit (major).

By severity: 9 major · 166 moderate · 43 minor.

From our pharmacist’s overview on the Tasimelteon page

“Tasimelteon (Hetlioz) resets the body clock in people with non-24-hour sleep-wake disorder, and the sleep aids they often reach for, melatonin and kava among them, sit on an interaction list that deserves real respect. Nine of the 218 ingredients on file rate major, mostly in two directions: sedatives like kava stack drowsiness onto a…”

Reviewed by 2 · Jul 18, 2026

Open the Tasimelteon 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 Tasimelteon, 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 Tasimelteon 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%

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

29 days ago today
Medication Tasimelteon
Steady interest

#2,232 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 Tasimelteon 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 Tasimelteon

What Is Tasimelteon Used For?

Brand names: Hetlioz, Hetlioz Lq

Tasimelteon capsules are approved to treat Non-24-Hour Sleep-Wake Disorder (Non-24) in adults. Non-24 is a condition where the body's internal clock does not align with the normal 24-hour day, causing sleep and wake times to shift continuously.

Hetlioz capsules are also approved to treat nighttime sleep disturbances in Smith-Magenis Syndrome (SMS) in patients 16 years of age and older. Hetlioz LQ oral suspension is approved specifically for nighttime sleep disturbances in SMS in pediatric patients ages 3 to 15 years.

Most-Reported Side Effects for Tasimelteon

From FAERS, the FDA’s public side-effect reporting system (5,770 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Insomnia 728 reports
Middle insomnia 414 reports
Somnolence 408 reports
Headache 386 reports
Nightmare 268 reports
See full Tasimelteon 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 Tasimelteon, 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 Tasimelteon Together: Common Questions

Is it safe to take Rhubarb with Tasimelteon?
We do not list a known interaction between Rhubarb and Tasimelteon. 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.
Should I take Rhubarb and Tasimelteon at the same time of day?
At least one FDA label for a product containing Tasimelteon 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 Tasimelteon on its own and move Rhubarb 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.
How was the Rhubarb and Tasimelteon combination checked?
Interactions in our licensed database are recorded against drug classes. Tasimelteon is filed under 5 classifications, and Rhubarb has documented interactions with 8 drug classes — none of Tasimelteon'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 — Tasimelteon 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 Tasimelteon interact with any supplements?
Yes. Tasimelteon has documented interactions with 218 supplements in our database — Rhubarb is not one of them. The Tasimelteon 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 Tasimelteon drug information The full plain-English guide to this medication Tasimelteon supplement interactions Every supplement checked against Tasimelteon, 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 Tasimelteon 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.