Drug & supplement interaction

Danshen + Tamoxifen Citrate

Tamoxifen Citrate brand names: Nolvadex, Soltamox.

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

Tamoxifen Citrate falls into 4 drug categories that Danshen can interact with; the most serious is rated moderate. Theoretically, danshen may increase the levels and clinical effects of drugs metabolized by CYP2C9.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions4
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Danshen and Tamoxifen Citrate

These two interact in 4 distinct ways. Each one is explained separately below.

Why Are There 4 Interactions?

Danshen interacts with whole categories of medication. Tamoxifen Citrate falls into 4 of those categories, so it can interact with Danshen in 4 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES

1 of 4

Why this applies to Tamoxifen Citrate

Tamoxifen Citrate falls under CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES — the group Danshen interacts with.

Theoretically, danshen may increase the levels and clinical effects of drugs metabolized by CYP2C9.
In vitro research shows that various constituents of danshen inhibit the activity of CYP2C9. So far, this interaction has not been reported in humans.
Severity Moderate 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 to know about pairing Danshen with tamoxifen. Lab studies suggest Danshen can slow down an enzyme in your liver called CYP2C9, which is one of the enzymes that helps process tamoxifen. In theory, if that enzyme is blocked, more tamoxifen could linger in your body. That might mean stronger effects, including a higher chance of side effects like hot flashes, nausea, or a small added risk of blood clots.

I want to be honest, though: this is only seen in test-tube and animal research, not in real people, so it's quite uncertain. Danshen may also affect blood clotting on its own. Because tamoxifen is such an important medicine, please loop in your oncologist or pharmacist before adding Danshen rather than starting or stopping anything yourself.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Wang X, Cheung CM, Lee WY, Or PM, Yeung JH. Major tanshinones of Danshen (Salvia miltiorrhiza) exhibit different modes of inhibition on human CYP1A2, CYP2C9, CYP2E1 and CYP3A4 activities in vitro. Phytomedicine. 2010 Sep;17(11):868-75. PubMed
Moderate

P-GLYCOPROTEIN SUBSTRATES

2 of 4

Tamoxifen Citrate also falls under P-GLYCOPROTEIN SUBSTRATES.

Danshen might alter the levels of drugs cleared by p-glycoprotein.
Pharmacokinetic research in healthy volunteers suggests that danshen might affect p-glycoprotein activity. Taking danshen extract 1 gram three times daily for 10 days prior to receiving fexofenadine 60 mg increases peak levels of fexofenadine, a p-glycoprotein substrate, by 27.4% and area under the curve (AUC) by 37.2%.
Severity Moderate Likelihood Possible Evidence B

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 gist for you. Tamoxifen is moved around your body partly by a transporter pump called P-glycoprotein. Danshen may slow that pump down. In a small study, danshen raised blood levels of another pump-dependent drug by about a third. So in theory, danshen could nudge tamoxifen levels a bit higher.

If that happens, you might notice more of tamoxifen's usual effects, like hot flashes, leg swelling, or nausea. Honestly, the evidence here is thin and based on a different drug, so we can't say for sure it matters for tamoxifen. Still, because tamoxifen is a serious cancer medicine, please run any danshen product by your oncologist or pharmacist first rather than adding it on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Qiu F, Zeng J, Liu S, He M, Zhu L, Ye Y, Miao P, Shen S, Jiang J. Effects of danshen ethanol extract on the pharmacokinetics of fexofenadine in healthy volunteers. Evid Based Complement Alternat Med. 2014;2014:473213. PubMed
Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

3 of 4

Tamoxifen Citrate also falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES.

Danshen might alter the levels and clinical effects of drugs metabolized by CYP3A4.
Preliminary clinical research in healthy males shows that the administration of danshen for 10-14 days induces intestinal CYP3A4 and increases the clearance of midazolam, a CYP3A4 substrate. The maximum concentration of midazolam was decreased by 31% to 67%, and drug levels were decreased by 27% to 80%. However, a single dose of danshen has the opposite effect, increasing maximum concentrations of midazolam by 87%.
Severity Moderate Likelihood Possible Evidence B

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 something worth knowing about tamoxifen: it's actually a prodrug, meaning your body has to convert it into its active forms (like endoxifen) before it can fight breast cancer. Several liver enzymes do this work, including CYP3A4. Danshen has been shown to nudge CYP3A4 activity around, and over a week or two of regular use it tends to speed up this enzyme.

The concern with tamoxifen is that messing with these enzymes could change how much active drug you end up with, and since this medicine is doing such an important job, even modest shifts matter. The evidence here is fairly limited and mostly comes from a study using a different drug, so the real-world effect on tamoxifen isn't fully proven. Still, I'd play it safe. Please check with your oncologist or pharmacist before adding Danshen rather than starting or stopping anything on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Qiu F, Wang G, Zhang R, Sun J, et al. Effect of danshen extract on the activity of CYP3A4 in healthy volunteers. Br J Clin Pharmacol 2010;69:656-62. PubMed
  2. Qiu F, Jiang J, Ma Y, Wang G, Gao C, Zhang X, Zhang L, Liu S, He M, Zhu L, Ye Y, Li Q, Miao P. Opposite Effects of Single-Dose and Multidose Administration of the Ethanol Extract of Danshen on CYP3A in Healthy Volunteers. Evid Based Complement Alternat Me PubMed
Moderate

GLUCURONIDATED DRUGS

4 of 4

Tamoxifen Citrate also falls under GLUCURONIDATED DRUGS.

Theoretically, danshen might affect the levels and clinical effects of drugs requiring glucuronidation.
In vitro research shows that danshen induces the expression of glucuronosyltransferases. However, it also inhibits the activity of glucuronosyltransferases, including various members of the 1A and 2B families. The extent of inhibition of a specific glucuronosyltransferase seems to be dependent on whether or not the danshen is processed via 'sweating'. This type of processing may affect the levels of constituents in danshen that alter glucuronosyltransferase activity. So far, this interaction has not been reported in humans.
Severity Moderate 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 honest picture with Danshen and tamoxifen. Your body partly clears tamoxifen and its active forms by attaching a sugar molecule to them, a step called glucuronidation. In lab studies, Danshen seems to tug on those enzymes in both directions, sometimes speeding them up, sometimes slowing them down, depending on how the root was processed. So we can't reliably predict which way tamoxifen levels would shift.

The good news: this is only test-tube and animal data, and it has never actually been reported in people. Still, tamoxifen is a long-term cancer medicine where you want steady, predictable levels, so I wouldn't add a Danshen supplement on your own. Run it by your oncologist or pharmacist first, and they can decide if it's worth the unknown.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Liu J, Shi Y, Wu C, et al. Comparison of sweated and non-sweated ethanol extracts of Salvia miltiorrhiza Bge. (Danshen) effects on human and rat hepatic UDP-glucuronosyltransferase and preclinic herb-drug interaction potential evaluation. Curr Drug Metab

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

Danshen Also Interacts With Other Medications

Danshen has 123 major, 935 moderate known drug interactions in our database — the Tamoxifen Citrate one above is among them. If you take anything else, check it against the full list below.

Major 123 Moderate 935 No known interaction 1,772 (incl. Tamoxifen Citrate)
Taking anything else?

Check Another of Your Medications Against Danshen

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

From our Q&A

Questions About Danshen or Tamoxifen Citrate

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Danshen or Tamoxifen Citrate, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Tamoxifen Citrate

This page covers Danshen only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tamoxifen Citrate page lists 210 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 11 major · 166 moderate · 33 minor.

From our pharmacist’s overview on the Tamoxifen Citrate page

“Tamoxifen (Nolvadex, Soltamox) often stands between a breast cancer patient and a recurrence, so the stakes on this page run higher than usual. Eleven of the 210 supplements and herbs on file carry a major rating, and those eleven deserve your attention ahead of everything else.”

Reviewed by 2 · Jul 18, 2026

Open the Tamoxifen Citrate interaction page

One more smart check

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

We hold 18 real supplement products containing Danshen, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Danshen. Your product may carry other ingredients that interact with Tamoxifen Citrate too, on top of Danshen — 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 Danshen and Tamoxifen Citrate 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 Danshen
Top half

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

29 days ago today
Medication Tamoxifen Citrate
Top 25%

#468 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 Danshen

What is Danshen?

Danshen
  • Heart and circulation support
  • Angina (chest pain)
  • High blood pressure
  • Anxiety and stress
  • Liver health

Danshen is a root used in traditional Chinese medicine, mainly for heart and circulation problems. Some early research is promising, but the evidence is not strong enough to confirm it works for any condition, and it may affect blood clotting. Talk to a pharmacist or doctor before using it, especially if you take other medicines or have a health condition.

Read the full Danshen monograph & all interactions
Medication

About Tamoxifen

What Is Tamoxifen Used For?

Brand names: Nolvadex, Soltamox

Tamoxifen is used to treat estrogen receptor-positive metastatic breast cancer in both women and men, and as follow-up (adjuvant) therapy after surgery for early-stage breast cancer in women. It also reduces the occurrence of cancer in the opposite breast when used as adjuvant therapy.

In women with ductal carcinoma in situ (DCIS — an early, non-invasive breast change) following surgery and radiation, tamoxifen lowers the risk of developing invasive breast cancer. It is also approved to reduce the risk of breast cancer in women who are at high risk but have not yet been diagnosed. Both Tamoxifen Citrate tablets and Soltamox oral solution share these indications.

See full Tamoxifen drug information
Keep checking

Other Drugs & Danshen

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

123Major
935Moderate
0Minor
1,771No known interaction
123 Major 935 Moderate 1,771 No interaction
Major

123 interactions

Showing 60 of 123 major interactions — see all 123 on the Danshen page.

Moderate

935 interactions

Showing 60 of 935 moderate interactions — see all 935 on the Danshen page.

No interaction 1,771 drugs checked — show the list

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

Showing the 60 most looked-up of 1,771 medications checked with no known interaction — see the full Danshen list.

See the full Danshen interactions page
See every supplement checked against Tamoxifen Citrate, 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
Danshen monograph › Uses, safety, and every drug interaction in one place Tamoxifen Citrate supplement interactions › Every supplement checked against Tamoxifen Citrate, ranked by severity Tamoxifen 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 Danshen and Tamoxifen Citrate Together: Common Questions

Can you take Danshen with Tamoxifen Citrate?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
Why are there 4 interactions listed for Danshen and Tamoxifen Citrate?
Tamoxifen Citrate belongs to more than one drug category, and Danshen interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Danshen and Tamoxifen Citrate interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Tamoxifen Citrate and Danshen?

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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.