Drug & supplement interaction

Sweet Violet + Lapatinib

Lapatinib brand name: Tykerb.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Sweet Violet 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

Sweet Violet 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 Sweet Violet 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 Sweet Violet 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.

Sweet Violet safety at a glance

Sweet Violet overall Use caution Generally regarded as gentle in small culinary or tea amounts, but human safety data are limited.
Pregnancy Avoid Not enough safety information is available, so it is best avoided during pregnancy.
Breastfeeding Avoid There is not enough information to know if it is safe while breastfeeding, so avoid it.

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

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

What Lapatinib’s Own FDA Label Lists

This is not an interaction — none of it involves Sweet Violet. These are the most notable effects listed in the ADVERSE REACTIONS section of Lapatinib’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both.

  • Diarrhea mentioned in 27.1% of FDA reports for Lapatinib
  • Acne
  • Mouth irritation or sores
  • Tiredness mentioned in 8.5% of FDA reports for Lapatinib
  • Vomiting mentioned in 7.8% of FDA reports for Lapatinib
  • A skin rash mentioned in 6.9% of FDA reports for Lapatinib
  • Nausea mentioned in 10.5% of FDA reports for Lapatinib

From the ADVERSE REACTIONS section of the FDA label for Lapatinib. Read the label on DailyMed › Where a percentage is shown, it is the share of 15,427 voluntary FDA FAERS reports for Lapatinib that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Sweet Violet’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Sweet Violet side to compare — that is a limit of the record, not a statement that Sweet Violet has no side effects.

Everything else you take

See Every Supplement That Interacts With Lapatinib

This page covers Sweet Violet 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

One more smart check

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

We hold 14 real supplement products containing Sweet Violet, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Sweet Violet. Even though Sweet Violet itself has no known interaction with Lapatinib, 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 Sweet Violet 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 Sweet Violet
Steady interest

#1,226 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Lapatinib
Steady interest

#2,248 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 Sweet Violet reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Sweet Violet and Lapatinib records this page draws on were last updated June 22, 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 Sweet Violet

What is Sweet Violet?

  • Cough and sore throat
  • Bronchitis and chest congestion
  • Trouble sleeping
  • Skin irritation
  • Mild constipation
  • Headache

Sweet Violet is a traditional herb used mainly as a soothing remedy for coughs, sore throats, and minor respiratory complaints. Modern scientific evidence supporting these uses is very limited, so it should not replace proven treatments. It is generally considered gentle in food-like amounts, but talk with your pharmacist or doctor before using it, especially if you are pregnant, breastfeeding, or giving it to a child.

Viola odorata · Violaceae · Flowers, leaves, and roots; sometimes the whole plant · Tea (infusion), syrup, dried herb, tincture, and topical preparations

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

Sweet Violet: dosing

There is no standardized or officially established dose for Sweet Violet. Traditional use most often involves a tea made from the dried flowers or leaves, or a syrup for cough, but exact amounts vary widely between products and recipes.The safest approach is to follow the directions on the product label and not exceed the recommended amount.

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

Read the full Sweet Violet 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 & Sweet Violet

Browse every other medication we’ve checked against Sweet Violet — 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
No interaction 2,829 drugs checked — show the list
Evidence & sources

Sweet Violet References

The 8 references that drive our Sweet Violet 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. Beiraghdar F, Einollahi B, Ghadyani A, et al. A two-week, double-blind, placebo-controlled trial of Viola odorata, Echium amoenum and Physalis alkekengi mixture in symptomatic benign prostate hyperplasia (BPH) men. Pharm Biol 2017;55(1):1800-5.
  2. Qasemzadeh MJ, Sharifi H, Hamedanian M, et al. The effect of Viola odorata flower syrup on the cough of children with asthma: a double-blind, randomized controlled trial. J Evid Based Complementary Altern Med 2015;20(4):287-91. doi: 10.1177/21565872155848 PubMed
  3. Feyzabadi Z, Rezaeitalab F, Badiee S, et al. Efficacy of Violet oil, a traditional Iranian formula, in patients with chronic insomnia: A randomized, double-blind, placebo-controlled study. J Ethnopharmacol 2018;214:22-8. doi: 10.1016/j.jep.2017.11.036. PubMed
  4. Shayesteh M, Vaez-Mahdavi MR, Shams J, et al. Effects of Viola odorata as an Add-On Therapy on Insomnia in Patients with Obsession or Depression: A Pilot Randomized Double-Blind Placebo-Controlled Trial. J Altern Complement Med 2020;26(5):398-408.
  5. Taherzadeh Z, Khaluyan H, Iranshahy M, Rezaeitalab F, Eshaghi Ghalibaf MH, Javadi B. Evaluation of sedative effects of an intranasal dosage form containing saffron, lettuce seeds and sweet violet in primary chronic insomnia: A randomized, double-dummy, do
  6. Tafazoli V, Shahriari M, Heydari M, Nikbakht HA, Zarshenaas MM, Nimrouzi M. The Effect of Viola Odorata L. Oil for Fever in Children: A Randomized Triple-blinded Placebo-controlled Clinical Trial. Curr Drug Discov Technol 2020;17(5):696-703. PubMed
  7. Yazdi N, Kardooni M, Namjuyan F, Vardanjani HM, Tafazoli V, Jaladat AM. Efficacy of Sweet Violet (Viola odorata) flower oil on the symptoms of adults with allergic rhinitis: A double-blind randomized placebo-controlled clinical trial. Complement Ther Med PubMed
  8. Saffar Shahroodi A, Nejabat M, Nimrouzi M, Aghaei H, Salehi A, Rezaei Mokarram A. Effects of intranasal administration of violet oil in dry eye disease. Clin Exp Optom 2019;102(6):576-582. 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 Sweet Violet and Lapatinib Together: Common Questions

Is it safe to take Sweet Violet with Lapatinib?
We do not list a known interaction between Sweet Violet 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 — Sweet Violet 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

Still Have a Question About Lapatinib and Sweet Violet?

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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.