Drug & supplement interaction

Tormentil + Lapatinib

Lapatinib brand name: Tykerb.

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 Tormentil and Lapatinib 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.

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Interaction report

Tormentil and Lapatinib

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 Lapatinib and Tormentil 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Tormentil at all — not against Lapatinib, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Tormentil safety at a glance

Tormentil overall Use caution Generally considered low-risk for short-term use, but human safety data are limited.
Pregnancy Avoid Not enough safety information, so it is best avoided during pregnancy.
Breastfeeding Avoid Safety has not been studied, so avoid use while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Lapatinib and Tormentil? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Tormentil Itself Has Been Linked To

This is not an interaction — nothing below involves Lapatinib. It is the side-effect record for Tormentil on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Tormentil, this list is the first place to look.

  • Heartburn / Stomach pain Additional detail

    “Orally, tormentil has been reported to cause mild abdominal pain, heartburn, and feelings of fullness in one clinical trial. These adverse effects occurred at the same frequency for doses ranging from 1.2 grams daily to 3 grams daily.”

    Tormentil · Natural Medicines adverse-effect record, reported in dyspepsia.

    1 source cited
    1. 78590. Huber, R., Ditfurth, A. V., Amann, F., Guthlin, C., Rostock, M., Trittler, R., Kummerer, K., and Merfort, I. Tormentil for active ulcerative colitis: an open-label, dose-escalating study. J.Clin.Gastroenterol. 2007;41(9):834-838. PubMed

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

Everything else you take

See Every Supplement That Interacts With Lapatinib

This page covers Tormentil only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Lapatinib page lists 143 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Adrafinil (moderate).

By severity: 3 major · 100 moderate · 40 minor.

From our pharmacist’s overview on the Lapatinib page

“Of the 143 supplements on file for lapatinib (Tykerb), nearly all press on the same point, the CYP3A4 enzyme that clears this HER2-targeted breast cancer drug. That deserves real caution, since lapatinib only works when its blood level stays in range.”

Reviewed by 2 · Jul 18, 2026

Open the Lapatinib interaction page

How much people look this up

Where Tormentil and Lapatinib 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 Tormentil
Steady interest

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

29 days ago today
Medication Lapatinib
Steady interest

#1,518 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 Tormentil reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Tormentil and Lapatinib 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 Tormentil

What is Tormentil?

  • Diarrhea
  • Mouth and throat inflammation
  • Mild digestive upset
  • Sore throat (gargle)
  • Minor wounds and skin irritation

Tormentil is a traditional herb whose root is rich in tannins and has long been used for diarrhea and as a mouth rinse for sore gums or throat. Some small studies suggest it may help shorten diarrhea, but overall evidence is limited and quality is low. Talk to your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding because safety is not established.

Potentilla erecta · Rosaceae · Root and rhizome (underground stem) · Tincture, liquid extract, tea, capsules, mouth rinse

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

Tormentil: dosing

There is no official, standardized dose for tormentil, and products vary widely in strength. Tinctures, extracts, teas, and capsules will each have different recommended amounts.The safest approach is to follow the directions on the product label and not exceed them. If you are using it as a mouth rinse, do not swallow large amounts.

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

Read the full Tormentil monograph & all interactions
Medication

About Lapatinib

What Is Lapatinib Used For?

Brand name: Tykerb

Lapatinib tablets — sold under the brand name Tykerb — are used to treat advanced or metastatic breast cancer in patients whose tumors overexpress the HER2 protein. They are always used in combination with another medicine, not alone.

Tykerb is approved in combination with capecitabine for HER2-positive advanced or metastatic breast cancer in patients who have already received prior treatment including an anthracycline, a taxane, and trastuzumab, and whose disease has progressed on trastuzumab. Tykerb is also approved in combination with letrozole for postmenopausal women with hormone receptor-positive, HER2-positive metastatic breast cancer when hormonal therapy is appropriate.

Most-Reported Side Effects for Lapatinib

From FAERS, the FDA’s public side-effect reporting system (15,427 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Diarrhea 4,174 reports
Nausea 1,615 reports
Fatigue 1,305 reports
Vomiting 1,209 reports
Rash 1,061 reports
See full Lapatinib drug information
Keep checking

Other Drugs & Tormentil

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Tormentil list.

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

Tormentil References

The 1 references that drive our Tormentil 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. Huber, R., Ditfurth, A. V., Amann, F., Guthlin, C., Rostock, M., Trittler, R., Kummerer, K., and Merfort, I. Tormentil for active ulcerative colitis: an open-label, dose-escalating study. J.Clin.Gastroenterol. 2007;41(9):834-838. PubMed

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 Tormentil and Lapatinib Together: Common Questions

Is it safe to take Tormentil with Lapatinib?
We do not list a known interaction between Tormentil and Lapatinib. 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.
Does Lapatinib interact with any supplements?
Yes. Lapatinib has documented interactions with 143 supplements in our database — Tormentil is not one of them. The Lapatinib 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

Tormentil monograph Uses, safety profile, and every drug interaction in one place Lapatinib drug information The full plain-English guide to this medication Lapatinib supplement interactions Every supplement checked against Lapatinib, 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 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Lapatinib and Tormentil?

Our pharmacists answer your medication & supplement questions — free.

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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.