Drug & supplement interaction

Mastic + 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 Mastic 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. 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

Mastic 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 Mastic 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 Mastic 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.

Mastic safety at a glance

Mastic overall Use caution Generally well tolerated in food and traditional amounts, but supplement-strength data are limited.
Pregnancy Avoid Not enough safety information; best to avoid medicinal amounts during pregnancy.
Breastfeeding Avoid Not enough safety information; best to avoid medicinal amounts while breastfeeding.

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

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

No Interaction Found — But Data Suggests Mastic and Lapatinib 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.

  • Diarrhea / Nausea reported in 27.1% of FDA reports for Lapatinib Additional detail

    Mastic

    “Orally, nausea, diarrhea, and constipation have been rarely reported following use of mastic gum. In one case, constipation ceased two days after discontinuing mastic gum.”

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

    3 sources cited
    1. 62051. Kaliora, A. C., Stathopoulou, M. G., Triantafillidis, J. K., Dedoussis, G. V., and Andrikopoulos, N. K. Chios mastic treatment of patients with active Crohn's disease. World J Gastroenterol. 2-7-2007;13(5):748-753. PubMed
    2. 62069. Dabos, K. J., Sfika, E., Vlatta, L. J., and Giannikopoulos, G. The effect of mastic gum on Helicobacter pylori: a randomized pilot study. Phytomedicine. 2010;17(3-4):296-299. PubMed
    3. 62071. Dabos, K. J., Sfika, E., Vlatta, L. J., Frantzi, D., Amygdalos, G. I., and Giannikopoulos, G. Is Chios mastic gum effective in the treatment of functional dyspepsia? A prospective randomised double-blind placebo controlled trial. J Ethnopharmacol. 2-3-20 PubMed

    Lapatinib

    Listed in the ADVERSE REACTIONS section of the FDA label for Lapatinib, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • A skin rash reported in 6.9% of FDA reports for Lapatinib Additional detail

    Mastic

    “Subcutaneously, administration of a specific mastic extract (RPh201, Regenera Pharma) has been most commonly reported to cause injection site pain and erythema. Pruritus, rash, and ecchymosis have also been reported with this extract.

    Topically, use of a specific mastic gum- and storax gum-containing product (Mastisol Liquid Adhesive, Ferndale Laboratories) has been associated with cases of allergic contact dermatiti…”

    Mastic · Natural Medicines adverse-effect record, reported in dermatitis.

    2 sources cited
    1. 103266. Hazan Z, Adamsky K, Lucassen A, Levin LA. A first-in-human phase 1 randomized single and multiple ascending dose study of RPh201 in healthy volunteers. Clin Pharmacol Drug Dev. 2020;9(3):366-74. PubMed
    2. 106467. Moraschini V, Kischinhevsky ICC, Calasans-Maia MD, et al. Ineffectiveness of ozone therapy in nonsurgical periodontal treatment: a systematic review and metaanalysis of randomized clinical trials. Clin Oral Investig 2020;24(6):1877-1888. PubMed

    Lapatinib

    Listed in the ADVERSE REACTIONS section of the FDA label for Lapatinib, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Reported for Mastic but not commonly for Lapatinib: constipation, bleeding or bruising, dizziness and headache.

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

Overlapping uses

What Lapatinib Is Prescribed For, and What Mastic Has Been Studied For

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

Lapatinib is prescribed for: 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.

Mastic has been studied for:

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

    Mastic for cancer

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

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 Lapatinib on your own; if you are taking Mastic 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 Lapatinib

This page covers Mastic 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 Mastic as Part of a Dietary Supplement Product? Check It for Interactions

We hold 104 real supplement products containing Mastic, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Mastic. Even though Mastic 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 Mastic 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 Mastic
Top half

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

29 days ago today
Medication Lapatinib
Steady interest

#1,576 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 Mastic reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Mastic 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 Mastic

What is Mastic?

Mastic
  • Indigestion and stomach upset
  • Stomach ulcers and H. pylori support
  • Oral and gum health
  • Bad breath
  • General antioxidant/anti-inflammatory support

Mastic is a resin from the mastic tree that has a long history of use for digestive complaints and oral health. Some small studies suggest it may help with indigestion, stomach ulcers, and dental hygiene, but the evidence is limited and not conclusive. It is generally well tolerated in food amounts, but talk to your pharmacist or doctor before using it as a supplement, especially if you are pregnant or breastfeeding.

Pistacia lentiscus · Anacardiaceae · Resin (gum) from the tree; sometimes the essential oil · Capsules, chewable gum/resin tears, powder, essential oil, mouthwash, toothpaste

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

Mastic: dosing

There is no official or standardized dose of mastic. Studies have used different forms and amounts, so it is hard to recommend one exact dose. The strength of capsules, powders, and chewing products can vary a lot between brands.The safest approach is to follow the directions on the product label and not exceed the suggested amount. Because supplements are not tightly regulated, choose a reputable brand when possible.

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

Read the full Mastic 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 & Mastic

Browse every other medication we’ve checked against Mastic — 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 Mastic 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 Mastic list.

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

Mastic References

The 5 references that drive our Mastic 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. Kaliora, A. C., Stathopoulou, M. G., Triantafillidis, J. K., Dedoussis, G. V., and Andrikopoulos, N. K. Chios mastic treatment of patients with active Crohn's disease. World J Gastroenterol. 2-7-2007;13(5):748-753. PubMed
  2. Dabos, K. J., Sfika, E., Vlatta, L. J., and Giannikopoulos, G. The effect of mastic gum on Helicobacter pylori: a randomized pilot study. Phytomedicine. 2010;17(3-4):296-299. PubMed
  3. Dabos, K. J., Sfika, E., Vlatta, L. J., Frantzi, D., Amygdalos, G. I., and Giannikopoulos, G. Is Chios mastic gum effective in the treatment of functional dyspepsia? A prospective randomised double-blind placebo controlled trial. J Ethnopharmacol. 2-3-20 PubMed
  4. Hazan Z, Adamsky K, Lucassen A, Levin LA. A first-in-human phase 1 randomized single and multiple ascending dose study of RPh201 in healthy volunteers. Clin Pharmacol Drug Dev. 2020;9(3):366-74. PubMed
  5. Moraschini V, Kischinhevsky ICC, Calasans-Maia MD, et al. Ineffectiveness of ozone therapy in nonsurgical periodontal treatment: a systematic review and metaanalysis of randomized clinical trials. Clin Oral Investig 2020;24(6):1877-1888. 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 Mastic and Lapatinib Together: Common Questions

Is it safe to take Mastic with Lapatinib?
We do not list a known interaction between Mastic 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.
Do Mastic and Lapatinib have any of the same side effects?
Yes — our sources link each of them separately to 3 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 Mastic and Lapatinib 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 Mastic in each. That is a conversation for your prescriber, especially if Lapatinib is being adjusted to a target.
Does Lapatinib interact with any supplements?
Yes. Lapatinib has documented interactions with 143 supplements in our database — Mastic 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

Mastic 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 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Lapatinib and Mastic?

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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.