Drug & supplement interaction

Yerba Mate + Thiotepa

Thiotepa brand names: Thioplex, Tepadina.

Minor Interaction
Medically reviewed by · Updated September 2026
The bottom line Minor

Yerba Mate has a minor interaction with Thiotepa. Theoretically, yerba mate might increase the levels and clinical effects of CYP3A4 substrates.

Read the full interaction report
SeverityMinor
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Yerba Mate and Thiotepa

Here is the interaction we found between these two, with the evidence behind it.

Minor

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

Why this applies to Thiotepa

Thiotepa falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Yerba Mate interacts with.

Theoretically, yerba mate might increase the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that yerba mate extract inhibits CYP3A4 enzymes. Theoretically, taking yerba mate may increase levels and adverse effects of CYP3A4 substrates.
Severity Minor Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the thing with thiotepa and yerba mate. Lab studies suggest yerba mate can mildly slow down an enzyme called CYP3A4. Thiotepa is a bit unusual because it's actually a prodrug, meaning your body uses CYP3A4 (and a related enzyme) to convert it into its active cancer-fighting form, called TEPA. So in theory, slowing that enzyme could shift how much active drug you make, which makes the direction here genuinely hard to predict.

The good news is this concern comes only from test-tube research, not real patients, so the actual risk is uncertain and likely small. Still, thiotepa is serious chemotherapy with side effects like low blood counts and nausea. Please check with your oncology team or pharmacist before drinking yerba mate during treatment.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Feltrin C, Farias IV, Sandjo LP, Reginatto FH, Simões CMO. Effects of Standardized Medicinal Plant Extracts on Drug Metabolism Mediated by CYP3A4 and CYP2D6 Enzymes. Chem Res Toxicol 2020;33(9):2408-2419. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Yerba Mate Also Interacts With Other Medications

Yerba Mate has 8 major, 505 moderate, 572 minor known drug interactions in our database — the Thiotepa one above is one of them. If you take anything else, check it against the full list below.

Major 8 Moderate 505 Minor 572 No known interaction 1,745 (incl. Thiotepa)
Taking anything else?

Check Another of Your Medications Against Yerba Mate

Covers the 2,830 medications we’ve checked against Yerba Mate. Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Thiotepa

This page covers Yerba Mate only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Thiotepa page lists 146 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 Acerola (moderate).

By severity: 3 major · 102 moderate · 41 minor.

From our pharmacist’s overview on the Thiotepa page

“Thiotepa (Thioplex, Tepadina) is chemotherapy, given for several cancers and to prepare patients for stem cell transplant, so its 146 supplement interactions make up a list to respect rather than skim. Three carry a major rating: grapefruit, St.”

Reviewed by 2 · Jul 18, 2026

Open the Thiotepa interaction page

One more smart check

Taking Yerba Mate as Part of a Dietary Supplement Product? Check It for Interactions

We hold 68 real supplement products containing Yerba Mate, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Yerba Mate. Your product may carry other ingredients that interact with Thiotepa too, on top of Yerba Mate — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Yerba Mate and Thiotepa 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 Yerba Mate
Top half

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

29 days ago today
Medication Thiotepa
Steady interest

#2,101 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.

Supplement

About Yerba Mate

What is Yerba Mate?

Yerba Mate
  • Energy and alertness
  • Weight loss
  • Mental focus
  • Digestive support
  • Antioxidant support

Yerba mate is a caffeine-containing herbal beverage from South America that is widely enjoyed for its stimulating, coffee-like effects. While it is rich in antioxidants and is being studied for weight, blood sugar, and cholesterol, strong human evidence for most health claims is limited. Drinking very hot mate over many years has been linked to higher risk of certain cancers, so enjoy it warm and in moderation.

Read the full Yerba Mate monograph & all interactions
Medication

About Thiotepa Injection

What Is Thiotepa Injection Used For?

Brand names: Thioplex, Tepadina

Tepadina (thiotepa) injection is used for several purposes. It treats adenocarcinoma (a type of cancer) of the breast or ovary. It is also used to control malignant effusions — abnormal fluid buildup in body cavities caused by cancer spreading to those areas. For bladder cancer, Tepadina treats superficial papillary carcinoma of the urinary bladder.

Tepadina is also used in pediatric patients with class 3 beta-thalassemia (a severe inherited blood disorder). In those patients, it is given as part of a preparative regimen — a conditioning treatment to reduce the risk of graft rejection before an allogeneic stem cell transplant (a transplant using donor stem cells), alongside the chemotherapy drugs busulfan and cyclophosphamide.

See full Thiotepa Injection drug information
Keep checking

Other Drugs & Yerba Mate

Browse every other medication we’ve checked against Yerba Mate — both the ones with a known interaction and the ones without. Select any drug for the full detail.

8Major
505Moderate
572Minor
1,744No known interaction
8 Major 505 Moderate 572 Minor 1,744 No interaction
Major

8 interactions

Moderate

505 interactions

Showing 60 of 505 moderate interactions — see all 505 on the Yerba Mate page.

Minor

572 interactions

Showing 60 of 572 minor interactions — see all 572 on the Yerba Mate page.

No interaction 1,744 drugs checked — show the list

We also checked Yerba Mate against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 1,744 medications checked with no known interaction — see the full Yerba Mate list.

See the full Yerba Mate interactions page
See every supplement checked against Thiotepa, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

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
Yerba Mate monograph › Uses, safety, and every drug interaction in one place Thiotepa supplement interactions › Every supplement checked against Thiotepa, ranked by severity Thiotepa Injection 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 Yerba Mate and Thiotepa Together: Common Questions

Can you take Yerba Mate with Thiotepa?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Yerba Mate and Thiotepa interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Thiotepa and Yerba Mate?

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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.