Drug & supplement interaction

European Five-finger Grass + Erlotinib

Erlotinib brand name: Tarceva.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated June 2026 · Pair last verified Oct 4, 2026

The bottom line No known interaction

We found no known interaction between European Five-finger Grass and Erlotinib 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 Erlotinib states a food rule worth keeping to.

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Interaction report

European Five-finger Grass and Erlotinib

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 Erlotinib and European Five-finger Grass 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 European Five-finger Grass at all — not against Erlotinib, 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.

European Five-finger Grass safety at a glance

European Five-fing... overall Use caution Limited safety data exist, so use it cautiously and at modest amounts.

Pregnancy Avoid Not enough safety information is available, so it is best avoided during pregnancy.

Breastfeeding Avoid Safety while breastfeeding is unknown, so avoid use unless cleared by your doctor.

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

Still wondering about combining Erlotinib and European Five-finger Grass? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

What to actually watch for

What Erlotinib’s Own FDA Label Lists

This is not an interaction — none of it involves European Five-finger Grass. These are the most notable effects listed in the ADVERSE REACTIONS section of Erlotinib’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. 10 of them are worth acting on rather than waiting out — marked below.

A stroke or mini-stroke Worth acting on
A bowel blockage Worth acting on
Severe muscle breakdown Worth acting on
Muscle weakness Worth acting on
Bleeding in the gut Worth acting on
A heart attack Worth acting on
Blood clots Worth acting on
Pancreatitis Worth acting on
Fainting Worth acting on
A severe skin reaction Worth acting on

Showing the 10 most notable of 39 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Erlotinib. Read the label on DailyMed › Where a percentage is shown, it is the share of 12,441 voluntary FDA FAERS reports for Erlotinib that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. European Five-finger Grass’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no European Five-finger Grass side to compare — that is a limit of the record, not a statement that European Five-finger Grass has no side effects.

How to take them

Some Erlotinib Products Have a Food Rule — European Five-finger Grass Should Not Break It

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

Recommended Dose – NSCLC The recommended daily dose of erlotinib tablets for NSCLC is 150 mg taken on an empty stomach, i.e., at least one hour before or two hours after the ingestion of food.

From the Dosage and Administration section of the FDA label we read for Erlotinib — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

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.

Everything else you take

See Every Supplement That Interacts With Erlotinib

This page covers European Five-finger Grass only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Erlotinib page lists 18 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Bilberry (moderate), Coffee Charcoal (moderate), European Mandrake (moderate) and Glucomannan (moderate).

By severity: 1 major · 8 moderate · 9 minor.

From our pharmacist’s overview on the Erlotinib page

“Activated charcoal is the entry I would flag first for anyone taking erlotinib (Tarceva), an oral targeted therapy for certain lung cancers. Charcoal can adsorb the drug in the gut and cut how much reaches the bloodstream, and with a cancer pill, less absorbed means less cancer fought.”

Reviewed by 2 · Jul 18, 2026

Open the Erlotinib interaction page

How much people look this up

Where European Five-finger Grass and Erlotinib 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 European Five-finger Grass

Steady interest

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

29 days ago today

Medication Erlotinib

Top half

#1,207 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. European Five-finger Grass is not yet covered by that licensed database, so its write-up cites publicly available medical sources directly (see the references below).
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every European Five-finger Grass reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The European Five-finger Grass and Erlotinib 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 Dr. Brian Staiger, PharmD, BCPS.

Supplement

About European Five-finger Grass

What is European Five-finger Grass?

Diarrhea
Sore throat and mouth rinse
Skin irritation
Mild inflammation
Digestive upset

European Five-finger Grass (Potentilla reptans) is a traditional European herb used mainly for diarrhea, sore throat, and minor skin problems, largely because of its tannin content. There is very little high-quality human research to confirm it works for any condition, so use it cautiously and talk to your pharmacist or doctor first.

Potentilla reptans · Rosaceae · Leaves, flowers, and roots (aerial parts and rhizome) · Tea, liquid extract, tincture, dried herb, topical preparations

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

European Five-finger Grass: dosing

There is no standardized, scientifically established dose for European Five-finger Grass. Traditional use most often involved a tea made from the dried leaves or roots, but exact amounts varied widely.If you choose to use a commercial product, follow the directions on the label and do not exceed the recommended amount. Because product strength can vary a lot between brands, it is wise to start low.

From our European Five-finger Grass monograph — the full record covers uses, side effects and every documented interaction.

Read the full European Five-finger Grass monograph & all interactions

Medication

About Erlotinib

What Is Erlotinib Used For?

Brand name: Tarceva

Erlotinib treats metastatic non-small cell lung cancer (NSCLC) when the tumor has certain EGFR gene changes (exon 19 deletions or exon 21 L858R mutations), found by an FDA-approved test. It can be used first, as maintenance, or after at least one prior chemotherapy regimen has stopped working.

Erlotinib is also used with gemcitabine as first-line treatment for locally advanced, unresectable or metastatic pancreatic cancer. These uses are listed for the erlotinib tablet products.

Most-Reported Side Effects for Erlotinib

From FAERS, the FDA’s public side-effect reporting system (12,441 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Diarrhea 1,339 reports

Rash 1,317 reports

Malignant neoplasm progression 890 reports

Fatigue 718 reports

Nausea 696 reports

See full Erlotinib drug information

Keep checking

Other Drugs & European Five-finger Grass

Browse every other medication we’ve checked against European Five-finger Grass — 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 European Five-finger Grass 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 European Five-finger Grass list.

See the full European Five-finger Grass interactions page

See every supplement checked against Erlotinib, ranked by severity

Evidence & sources

European Five-finger Grass References

The 2 sources that drive our European Five-finger Grass monograph — publicly available pages from reputable medical and government organizations. Every link was verified to work before publishing. European Five-finger Grass is not covered by the licensed Natural Medicines interaction database, so its page cites these public sources directly.

Herbs at a Glance — NIH National Center for Complementary and Integrative Health Source
Herbs and Supplements — MedlinePlus Source

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 European Five-finger Grass and Erlotinib Together: Common Questions

Is it safe to take European Five-finger Grass with Erlotinib?

We do not list a known interaction between European Five-finger Grass and Erlotinib. 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 European Five-finger Grass and Erlotinib at the same time of day?

At least one FDA label for a product containing Erlotinib 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 Erlotinib on its own and move European Five-finger Grass 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.

Does Erlotinib interact with any supplements?

Yes. Erlotinib has documented interactions with 18 supplements in our database — European Five-finger Grass is not one of them. The Erlotinib 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

European Five-finger Grass monograph Uses, safety profile, and every drug interaction in one place Erlotinib drug information The full plain-English guide to this medication Erlotinib supplement interactions Every supplement checked against Erlotinib, 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 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Erlotinib and European Five-finger Grass?

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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.