Drug & supplement interaction

Theaflavin + Atezolizumab

Atezolizumab brand name: Tecentriq.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated June 2026 · Pair last verified Sep 13, 2026

The bottom line No known interaction

We found no known interaction between Theaflavin and Atezolizumab 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

Theaflavin and Atezolizumab

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 Atezolizumab and Theaflavin 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.

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.

Theaflavin safety at a glance

Theaflavin overall Use caution Black tea is generally safe in normal amounts, but concentrated extracts are less studied.

Pregnancy Use caution Limit caffeine-containing tea and avoid high-dose extracts unless your doctor approves.

Breastfeeding Use caution Caffeine passes into breast milk, so limit intake and avoid concentrated extracts.

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

Still wondering about combining Atezolizumab and Theaflavin? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Atezolizumab

Interactions in our licensed database are recorded against drug classes, not just single drug names. Atezolizumab is filed under 2 classifications — antineoplastics, immunosuppressants. Theaflavin has documented interactions with 2 drug classes — the most serious being antidiabetes drugs (moderate) and organic anion-transporting polypeptide substrates (oatp) (moderate) — and none of Atezolizumab’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Theaflavin Does Interact With Other Medications

Theaflavin has 130 moderate known drug interactions in our database — Atezolizumab isn’t one of them. If you take anything else, check it against the full list below.

Moderate 130 No known interaction 2,700 (incl. Atezolizumab)

Taking anything else?

Check Another of Your Medications Against Theaflavin

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

What to actually watch for

What Atezolizumab’s Own FDA Label Lists

This is not an interaction — none of it involves Theaflavin. These are the most notable effects listed in the ADVERSE REACTIONS section of Atezolizumab’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.

Low magnesium Worth acting on
A change in thyroid levels Worth acting on
A stroke or mini-stroke Worth acting on
A bowel blockage Worth acting on
Dehydration Worth acting on
High potassium Worth acting on
Low sodium Worth acting on
Low potassium Worth acting on
A heart attack Worth acting on
Blood clots Worth acting on

Showing the 10 most notable of 50 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 Atezolizumab. Read the label on DailyMed › Theaflavin’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Theaflavin side to compare — that is a limit of the record, not a statement that Theaflavin has no side effects.

Everything else you take

See Every Supplement That Interacts With Atezolizumab

This page covers Theaflavin only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Atezolizumab page lists 54 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Active Hexose Correlated Compound (ahcc) (moderate), Alfalfa (moderate), American Ginseng (moderate), Andrographis (moderate) and Ashwagandha (moderate).

By severity: 52 moderate · 2 minor.

From our pharmacist’s overview on the Atezolizumab page

“Atezolizumab (Tecentriq) is cancer immunotherapy, a drug designed to release the brakes on your own immune system so it can attack tumors. That mechanism explains why nearly every one of the 54 supplements and herbs on this page made the list: 53 are flagged because they appear to stimulate immune activity, based mostly on lab and anim…”

Reviewed by 2 · Jul 18, 2026

Open the Atezolizumab interaction page

One more smart check

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

We hold 11 real supplement products containing Theaflavin, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Theaflavin. Even though Theaflavin itself has no known interaction with Atezolizumab, 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 Theaflavin and Atezolizumab 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 Theaflavin

Top half

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

29 days ago today

Medication Atezolizumab

Steady interest

#2,320 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 Theaflavin reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Theaflavin and Atezolizumab 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 Theaflavin

What is Theaflavin?

Heart health and cholesterol support
Antioxidant support
Weight management
Blood sugar support
General wellness

Theaflavins are antioxidant compounds formed when tea leaves are oxidized to make black tea. Early research suggests they may help with cholesterol and provide antioxidant effects, but high-quality human evidence is limited and doses are not standardized. Drinking black tea is generally safe, but talk to your pharmacist or doctor before taking concentrated extracts.

Camellia sinensis · Theaceae · Leaves (fermented/oxidized, as in black tea) · Black tea, standardized black tea extract capsules, tablets, powders

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

Theaflavin: dosing

There is no established standard dose of theaflavin. Supplements vary widely in how much theaflavin they contain and how the black tea extract is standardized.If you choose to take a product, follow the directions on the label and do not exceed the recommended amount. Drinking black tea is a simpler, well-tolerated way to get theaflavins for most people.

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

Read the full Theaflavin monograph & all interactions

Medication

About Atezolizumab Injection

What Is Atezolizumab Injection Used For?

Brand name: Tecentriq

Tecentriq (atezolizumab) is used to treat a range of cancers in adults. It can be used alone or combined with other cancer medicines depending on the cancer type and stage. Approved uses include non-small cell lung cancer (NSCLC) — both after surgery and in metastatic (spread) disease — extensive-stage small cell lung cancer (ES-SCLC), unresectable or metastatic hepatocellular carcinoma (liver cancer), BRAF V600 mutation-positive melanoma, and muscle invasive bladder cancer after surgery.

Tecentriq is also approved — as a single agent — for adult and pediatric patients aged 2 and older with unresectable or metastatic alveolar soft part sarcoma (ASPS), a rare soft tissue cancer. Several of these uses require tumor testing (such as PD-L1 expression or specific gene mutations) before Tecentriq is selected as treatment.

See full Atezolizumab Injection drug information

Keep checking

Other Drugs & Theaflavin

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

0Major

130Moderate

0Minor

2,699No known interaction

130 Moderate 2,699 No interaction

Moderate

130 interactions

Showing 60 of 130 moderate interactions — see all 130 on the Theaflavin page.

No interaction 2,699 drugs checked — show the list

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

Showing the 60 most looked-up of 2,699 medications checked with no known interaction — see the full Theaflavin list.

See the full Theaflavin interactions page

See every supplement checked against Atezolizumab, ranked by severity

Evidence & sources

Theaflavin References

The 4 references that drive our Theaflavin 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.

Maron DJ, Lu GP, Cai NS, et al. Cholesterol-lowering effect of a theaflavin-enriched green tea extract: a randomized controlled trial. Arch Intern Med 2003;163:1448-53.. PubMed
Takemoto M, Takemoto H, Kouno H, Soeda T, Moriya T. A simple, enzymatic biotransformation method using fresh green tea leaves efficiently generates theaflavin-containing fermentation water that has potent physiological functions in mice and humans. Biol P PubMed
Kondo A, Narumi K, Okuhara K, et al. Black tea extract and theaflavin derivatives affect the pharmacokinetics of rosuvastatin by modulating organic anion transporting polypeptide (OATP) 2B1 activity. Biopharm Drug Dispos. 2019;40(8):302-306. PubMed
Gothandam K, Ganesan VS, Ayyasamy T, Ramalingam S. Antioxidant potential of theaflavin ameliorates the activities of key enzymes of glucose metabolism in high fat diet and streptozotocin - induced diabetic rats. Redox Rep. 2019;24(1):41-50. 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 Theaflavin and Atezolizumab Together: Common Questions

Is it safe to take Theaflavin with Atezolizumab?

We do not list a known interaction between Theaflavin and Atezolizumab. 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.

How was the Theaflavin and Atezolizumab combination checked?

Interactions in our licensed database are recorded against drug classes. Atezolizumab is filed under 2 classifications, and Theaflavin has documented interactions with 2 drug classes — none of Atezolizumab's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Theaflavin interact with any other medications?

Yes. Theaflavin has 130 documented drug interactions in our database — Atezolizumab is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Atezolizumab interact with any supplements?

Yes. Atezolizumab has documented interactions with 54 supplements in our database — Theaflavin is not one of them. The Atezolizumab 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

Theaflavin monograph Uses, safety profile, and every drug interaction in one place Atezolizumab Injection drug information The full plain-English guide to this medication Atezolizumab supplement interactions Every supplement checked against Atezolizumab, 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 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Atezolizumab and Theaflavin?

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.