Drug & supplement interaction

Water Avens + Erlotinib

Erlotinib brand name: Tarceva.

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 Water Avens 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

Water Avens 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 Water Avens 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 Water Avens 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.

Water Avens safety at a glance

Water Avens overall Not established Little modern safety data exists, so caution is advised.
Pregnancy Avoid Safety is not established, so avoid use during pregnancy.
Breastfeeding Avoid Safety is not established, so avoid use while breastfeeding.

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

Still wondering about combining Erlotinib and Water Avens? 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 Water Avens. 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 12,442 voluntary FDA FAERS reports for Erlotinib that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Water Avens’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Water Avens side to compare — that is a limit of the record, not a statement that Water Avens has no side effects.

How to take them

Some Erlotinib Products Have a Food Rule — Water Avens Should Not Break It

At least one FDA label for a product containing Erlotinib says to take it on an empty stomach. Most supplements — Water Avens 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 Water Avens 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 Water Avens 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 Water Avens 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 Water Avens
Steady interest

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

29 days ago today
Medication Erlotinib
Steady interest

#1,731 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. Water Avens 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 Water Avens reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Water Avens and Erlotinib records this page draws on were last updated July 11, 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 Water Avens

What is Water Avens?

  • Diarrhea and digestive upset
  • Sore throat and mouth irritation
  • Mild fever
  • General tonic
  • Astringent for minor wounds

Water avens is a traditional herb whose root has been used as an astringent for diarrhea, sore throats, and digestive complaints. There is very little modern scientific research to confirm that it works or to define a safe dose, so use it cautiously and talk with a pharmacist or doctor first.

Geum rivale · Rosaceae · Root and rhizome (occasionally aerial parts) · Dried root, tea/decoction, tincture

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

Water Avens: dosing

There is no established or standardized dose for water avens. Traditional use involved teas (decoctions) of the dried root or tinctures, but reliable, research-based dosing is not available.If you choose to use a product, follow the directions on the label and do not exceed them.

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

Read the full Water Avens monograph & all interactions
Medication

About Erlotinib

What Is Erlotinib Used For?

Brand name: Tarceva

Erlotinib tablets are used to treat metastatic non-small cell lung cancer (NSCLC) in patients whose tumors carry specific gene changes — EGFR exon 19 deletions or exon 21 (L858R) mutations — confirmed by an FDA-approved test. It can be used as a first-line treatment, as maintenance therapy, or after at least one prior chemotherapy has stopped working.

Erlotinib tablets are also used for the first-line treatment of locally advanced, unresectable, or metastatic pancreatic cancer — but only in combination with another chemotherapy drug called gemcitabine. Erlotinib is not recommended alongside platinum-based chemotherapy regimens.

Most-Reported Side Effects for Erlotinib

From FAERS, the FDA’s public side-effect reporting system (12,442 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Diarrhea 1,341 reports
Rash 1,316 reports
Malignant neoplasm progression 891 reports
Fatigue 719 reports
Nausea 696 reports
See full Erlotinib drug information
Keep checking

Other Drugs & Water Avens

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

See the full Water Avens interactions page
See every supplement checked against Erlotinib, ranked by severity
Evidence & sources

Water Avens References

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

  1. Herbs at a Glance — NIH National Center for Complementary and Integrative Health Source
  2. Herbs and Supplements — MedlinePlus (U.S. National Library of Medicine) 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 Water Avens and Erlotinib Together: Common Questions

Is it safe to take Water Avens with Erlotinib?
We do not list a known interaction between Water Avens 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 Water Avens 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 Water Avens 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 — Water Avens 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

Water Avens 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 Water Avens?

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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.