Drug & supplement interaction

Couch Grass + Olaparib

Olaparib brand name: Lynparza.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Couch Grass and Olaparib 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

Couch Grass and Olaparib

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 Olaparib and Couch 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 Couch Grass at all — not against Olaparib, 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.

Couch Grass safety at a glance

Couch Grass overall Use caution Generally considered well tolerated, but human safety data are limited.
Pregnancy Avoid Not enough safety information, so it is best avoided during pregnancy.
Breastfeeding Avoid Not enough safety information, so it is best avoided while breastfeeding.

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

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

What Olaparib’s Own FDA Label Lists

This is not an interaction — none of it involves Couch Grass. These are the most notable effects listed in the ADVERSE REACTIONS section of Olaparib’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. 8 of them are worth acting on rather than waiting out — marked below.

  • Blood clots Worth acting on
  • Anemia Worth acting on mentioned in 7.8% of FDA reports for Olaparib
  • A low platelet count Worth acting on
  • Raised blood pressure Worth acting on
  • Shortness of breath Worth acting on
  • A low white blood cell count Worth acting on
  • Liver problems Worth acting on
  • A higher chance of infection Worth acting on
  • A change in taste
  • Mouth irritation or sores

Showing the 10 most notable of 23 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 Olaparib. Read the label on DailyMed › Where a percentage is shown, it is the share of 20,798 voluntary FDA FAERS reports for Olaparib that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Couch Grass’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Couch Grass side to compare — that is a limit of the record, not a statement that Couch Grass has no side effects.

Everything else you take

See Every Supplement That Interacts With Olaparib

This page covers Couch Grass only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Olaparib page lists 138 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 · 94 moderate · 41 minor.

From our pharmacist’s overview on the Olaparib page

“Grapefruit is the first thing to drop if you take Olaparib (Lynparza). It blocks CYP3A4, the liver enzyme that clears this cancer drug, so levels can climb and side effects with them.”

Reviewed by 2 · Jul 18, 2026

Open the Olaparib interaction page

One more smart check

Taking Couch Grass as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1,482 real supplement products containing Couch Grass, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Couch Grass. Even though Couch Grass itself has no known interaction with Olaparib, 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 Couch Grass and Olaparib 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 Couch Grass
Top 25%

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

29 days ago today
Medication Olaparib
Steady interest

#1,886 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.
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Couch Grass and Olaparib 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 Couch Grass

What is Couch Grass?

  • Urinary tract complaints
  • Mild bladder irritation
  • Increasing urine flow (diuretic)
  • Kidney 'gravel' or stones (traditional)
  • Soothing inflamed urinary passages
  • Sore throat or cough (traditional)

Couch grass is a common lawn weed whose rhizome has long been used in traditional European herbal medicine, mainly for urinary and bladder complaints. High-quality human studies are lacking, so its benefits are largely unproven. It is generally considered well tolerated, but you should talk to a pharmacist or doctor before using it, especially if you have kidney or heart problems.

Elymus repens · Poaceae · Dried rhizome (underground stem) and roots · Tea (infusion or decoction), liquid extract, tincture, capsules

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

Couch Grass: dosing

There is no well-established standardized dose of couch grass, because it has not been studied carefully in modern trials. Traditional preparations include teas made from the dried rhizome and liquid extracts or tinctures.The safest approach is to follow the directions on the product label and not exceed the recommended amount. If you take couch grass, drinking plenty of water is often advised, particularly when it is used for urinary complaints.

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

Read the full Couch Grass monograph & all interactions
Medication

About Olaparib

What Is Olaparib Used For?

Brand name: Lynparza

Lynparza (olaparib) is used to treat adults with certain ovarian, fallopian tube, or primary peritoneal cancers that carry BRCA or other DNA-repair gene mutations — both as a maintenance therapy after platinum-based chemotherapy (including in combination with bevacizumab for some patients) and for recurrent disease. It is also approved for HER2-negative breast cancer with a germline BRCA mutation, both in early high-risk disease (adjuvant setting) and in metastatic disease.

Lynparza is additionally used as maintenance therapy for adults with germline BRCA-mutated metastatic pancreatic adenocarcinoma whose disease has not progressed on first-line platinum-based chemotherapy, and for adults with certain gene-mutated metastatic castration-resistant prostate cancer — either alone (after prior enzalutamide or abiraterone) or in combination with abiraterone and prednisone or prednisolone. All uses require testing for specific genetic mutations using an FDA-approved companion diagnostic before starting treatment.

Most-Reported Side Effects for Olaparib

From FAERS, the FDA’s public side-effect reporting system (20,798 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Malignant neoplasm progression 2,063 reports
Nausea 1,827 reports
Fatigue 1,762 reports
Anemia 1,622 reports
Vomiting 724 reports
See full Olaparib drug information
Keep checking

Other Drugs & Couch Grass

Browse every other medication we’ve checked against Couch 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 Couch 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 Couch Grass list.

See the full Couch Grass interactions page
See every supplement checked against Olaparib, ranked by severity
Sources

Sources & How We Checked

We checked Couch Grass against Olaparib in the Natural Medicines interaction database and found no documented interaction on file. The medication overview comes from MedlinePlus, and supplement label details from the NIH Dietary Supplement Label Database.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Couch Grass monograph › Uses, safety, and every drug interaction in one place Olaparib supplement interactions › Every supplement checked against Olaparib, ranked by severity Olaparib drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Couch Grass and Olaparib Together: Common Questions

Is it safe to take Couch Grass with Olaparib?
We do not list a known interaction between Couch Grass and Olaparib. 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 Olaparib interact with any supplements?
Yes. Olaparib has documented interactions with 138 supplements in our database — Couch Grass is not one of them. The Olaparib 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 Olaparib and Couch Grass?

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.