Drug & supplement interaction

Black Cohosh + Diazepam

Diazepam brand names: Valium, Valium injection, Diastat AcuDial, Valtoco.

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 Black Cohosh and Diazepam 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 two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Black Cohosh and Diazepam

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 Diazepam and Black Cohosh 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.

Black Cohosh safety at a glance

Black Cohosh overall Use caution Generally well tolerated short-term, but rare liver concerns mean medical guidance is wise.
Pregnancy Possibly Unsafe When used orally in pregnant patients who are not at term. Black cohosh might have hormonal effects and menstrual and uterine stimulant effects. Theoretically,... Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used orally. Black cohosh might have hormonal effects. Theoretically, maternal intake of black cohosh might adversely affect a nursing child. Until more is... Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Diazepam and Black Cohosh? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Diazepam

Interactions in our licensed database are recorded against drug classes, not just single drug names. Diazepam is filed under 12 classifications — including benzodiazepines, anticonvulsants, cytochrome p450 2c19 (cyp2c19) substrates. Black Cohosh has documented interactions with 7 drug classes — the most serious being atorvastatin (lipitor) (moderate), cisplatin (platinol-aq) (moderate) and cytochrome p450 2d6 (cyp2d6) substrates (moderate) — and none of Diazepam’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

Black Cohosh Does Interact With Other Medications

Black Cohosh has 636 moderate, 16 minor known drug interactions in our database — Diazepam isn’t one of them. If you take anything else, check it against the full list below.

Moderate 636 Minor 16 No known interaction 2,178 (incl. Diazepam)
Taking anything else?

Check Another of Your Medications Against Black Cohosh

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

What to actually watch for

No Interaction Found — But Data Suggests Black Cohosh and Diazepam May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. One of them is worth acting on rather than waiting out — marked below.

  • Seizures Worth acting on Additional detail

    Black Cohosh

    “There has been a case report of severe complications, including seizures, renal failure, and respiratory distress, in an infant whose mother was given an unknown dose of black cohosh and blue cohosh at 42 weeks gestation to induce labor. However, this adverse effect may have been attributable to blue cohosh.”

    Black Cohosh · Natural Medicines adverse-effect record, reported in acute respiratory distress syndrome (ards).

    3 sources cited
    1. 1122. McFarlin BL, Gibson MH, O'Rear J, Harman P. A national survey of herbal preparation use by nurse-midwives for labor stimulation. Review of the literature and recommendations for practice. J Nurse Midwifery 1999;44:205-16. PubMed
    2. 9492. Gunn TR, Wright IM. The use of black and blue cohosh in labour. N Z Med J 1996;109:410-1.
    3. 9493. Baillie N, Rasmussen P. Black and blue cohosh in labour. N Z Med J 1997;110:20-1.

    “Orally, black cohosh may cause headache, dizziness, or tiredness. There is one case report of seizures in a female who used black cohosh, evening primrose oil, and chasteberry. A separate case report describes a 55-year-old female who experienced serotonin syndrome after the addition of black cohosh extract 40 mg daily to longstanding treatment with duloxetine 60 mg and sertraline 50 mg daily.

    In one case, an infant…”

    Black Cohosh · Natural Medicines adverse-effect record, reported in acute respiratory distress syndrome (ards).

    6 sources cited
    1. 35852. Oktem M, Eroglu D, Karahan HB, Taskintuna N, Kuscu E, Zeyneloglu HB. Black cohosh and fluoxetine in the treatment of postmenopausal symptoms: a prospective, randomized trial. Adv Ther 2007;24:448-61. PubMed
    2. 35886. Wong, V. C., Lim, C. E., Luo, X., and Wong, W. S. Current alternative and complementary therapies used in menopause. Gynecol.Endocrinol. 2009;25(3):166-174. PubMed
    3. 10988. Huntley A, Ernst E. A systematic review of the safety of black cohosh. Menopause 2003;10:58-64.. DOI
    4. 116172. Dernbach MR, Carpenter JE, Shah N, Carter GB. Black Cohosh Interactions with Prescription Medications Associated with Serotonin Toxicity and Rhabdomyolysis: A Case Report. J Emerg Med 2024;66(5):e592-e596. PubMed
    5. 9492. Gunn TR, Wright IM. The use of black and blue cohosh in labour. N Z Med J 1996;109:410-1.
    6. 9493. Baillie N, Rasmussen P. Black and blue cohosh in labour. N Z Med J 1997;110:20-1.

    Diazepam

    Listed in the ADVERSE REACTIONS section of the FDA label for Diazepam. Read the label on DailyMed ›

  • Tiredness / Headache reported in 4.8% of FDA reports for Diazepam Additional detail

    Black Cohosh

    “Orally, black cohosh is generally well tolerated when used in typical doses.

    Most Common Adverse Effects:

    Orally: Breast tenderness, dizziness, gastrointestinal upset, headache, irritability, rash, tiredness.

    Serious Adverse Effects (Rare):

    Orally: Endometrial hyperplasia and hepatotoxicity, although data are conflicting for both.”

    Black Cohosh · Natural Medicines adverse-effect record, reported in cluster headache.

    Diazepam

    Listed in the ADVERSE REACTIONS section of the FDA label for Diazepam, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • A skin rash Additional detail

    Black Cohosh

    Recorded for Black Cohosh in the same Natural Medicines adverse-effect record shown under Tiredness / Headache above.

    Diazepam

    Listed in the ADVERSE REACTIONS section of the FDA label for Diazepam. Read the label on DailyMed ›

Reported for Black Cohosh but not commonly for Diazepam: liver problems, stomach upset, shortness of breath and kidney problems.

Effects for Diazepam come from the ADVERSE REACTIONS section of its FDA label; effects for Black Cohosh come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 121,002 voluntary FDA FAERS reports for Diazepam that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Black Cohosh in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When used orally in pregnant patients who are not at term. Black cohosh might have hormonal effects and menstrual and uterine stimulant effects. Theoretically, this might increase the risk of miscarriage; avoid using during pregnancy. There is insufficient reliable information available about the safety of black cohosh when used to induce labor.

Lactation Possibly Unsafe

When used orally. Black cohosh might have hormonal effects. Theoretically, maternal intake of black cohosh might adversely affect a nursing child. Until more is known, nursing patients should avoid taking black cohosh.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Overlapping uses

What Diazepam Is Prescribed For, and What Black Cohosh Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Diazepam is a prescription medicine with approved uses on its FDA label. Black Cohosh is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Black Cohosh has been studied for:

  • Anxiety studied, not established Black Cohosh has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Black Cohosh for anxiety

    Black cohosh does not appear to be effective for treating anxiety in postmenopausal patients.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Diazepam on your own; if you are taking Black Cohosh for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Black Cohosh or Diazepam

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Black Cohosh or Diazepam, 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 Diazepam

This page covers Black Cohosh only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diazepam page lists 244 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Beer (major), Gamma-hydroxybutyrate (ghb) (major) and Grapefruit (major).

By severity: 9 major · 191 moderate · 44 minor.

Open the Diazepam interaction page

One more smart check

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

We hold 1,472 real supplement products containing Black Cohosh, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Cohosh. Even though Black Cohosh itself has no known interaction with Diazepam, 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 Black Cohosh and Diazepam 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 Black Cohosh
Top 25%

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

29 days ago today
Medication Diazepam
Top 5%

#119 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 Black Cohosh reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Black Cohosh and Diazepam 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 Black Cohosh

What is Black Cohosh?

Black Cohosh
  • Hot flashes and night sweats
  • Other menopause symptoms
  • Mood changes during menopause
  • Premenstrual syndrome (PMS)
  • Menstrual cramps

Black cohosh is a North American plant most often used to ease menopause symptoms like hot flashes, but the research is mixed and far from settled. It is generally well tolerated for short-term use, though rare reports of liver problems mean you should talk with your pharmacist or doctor before trying it, especially if you have liver disease.

Actaea racemosa · Ranunculaceae · Roots and rhizomes (underground stems) · Capsules, tablets, liquid extracts (tinctures), dried root for tea

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

Black Cohosh: dosing

There is no official standard dose of black cohosh. Many supplements are standardized to their triterpene glycoside content, and studies have used a range of amounts, so products can differ a lot from one another.The safest approach is to follow the directions on the product label and not exceed the recommended amount.

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

Read the full Black Cohosh monograph & all interactions
Medication

About Diazepam

What Is Diazepam Used For?

Brand names: Valium, Valium injection, Diastat AcuDial, Valtoco

  • Diazepam is used to relieve anxiety and to control agitation caused by alcohol withdrawal. It is also used along with other medications to control muscle spasms and spasticity caused by certain neurological disorders such as cerebral palsy (condition that causes difficulty with movement and balance), paraplegia (inability to move parts of the body), athetosis (abnormal muscle contractions), and stiff-man syndrome (a rare disorder with muscle rigidity and stiffness). Diazepam is also used along with other medications to control seizures. Diazepam is in a class of medications called benzodiazepines. It works by calming abnormal overactivity in the brain.

Most-Reported Side Effects for Diazepam

From FAERS, the FDA’s public side-effect reporting system (121,002 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Toxicity to various agents 9,514 reports
Drug abuse 7,212 reports
Nausea 6,288 reports
Fatigue 5,838 reports
Anxiety 5,086 reports
See full Diazepam drug information
Keep checking

Other Drugs & Black Cohosh

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

0Major
636Moderate
16Minor
2,177No known interaction
636 Moderate 16 Minor 2,177 No interaction
Moderate

636 interactions

Showing 60 of 636 moderate interactions — see all 636 on the Black Cohosh page.

Minor

16 interactions

No interaction 2,177 drugs checked — show the list

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

Showing the 60 most looked-up of 2,177 medications checked with no known interaction — see the full Black Cohosh list.

See the full Black Cohosh interactions page
See every supplement checked against Diazepam, ranked by severity
Evidence & sources

Black Cohosh References

The 68 references that drive our Black Cohosh 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.

  1. McFarlin BL, Gibson MH, O'Rear J, Harman P. A national survey of herbal preparation use by nurse-midwives for labor stimulation. Review of the literature and recommendations for practice. J Nurse Midwifery 1999;44:205-16. PubMed
  2. Whiting PW, Clouston A, Kerlin P. Black cohosh and other herbal remedies associated with acute hepatitis. Med J Aust 2002;177:440-3. PubMed
  3. Pepping J. Black cohosh: Cimicifuga racemosa. Am J Health Syst Pharm 1999;56:1400-2. PubMed
  4. Liske E. Therapeutic efficacy and safety of Cimicifuga racemosa for gynecologic disorders. Adv Ther 1998;15:45-53.
  5. Kruse SO, Lohning A, Pauli GF, et al. Fukiic and piscidic acid esters from the rhizome of Cimicifuga racemosa and the in vitro estrogenic activity of fukinolic acid. Planta Med 1999;65:763-4.
  6. Jacobson JS, Troxel AB, Evans J, et al. Randomized trial of black cohosh for the treatment of hot flashes among women with a history of breast cancer. J Clin Oncol 2001;19:2739-45. PubMed
  7. Gunn TR, Wright IM. The use of black and blue cohosh in labour. N Z Med J 1996;109:410-1.
  8. Baillie N, Rasmussen P. Black and blue cohosh in labour. N Z Med J 1997;110:20-1.
  9. Lontos S, Jones RM, Angus PW, Gow PJ. Acute liver failure associated with the use of herbal preparations containing black cohosh. Med J Aust 2003;179:390-1.. DOI
  10. Wuttke W, Seidlova-Wuttke D, Gorkow C. The Cimicifuga preparation BNO 1055 vs. conjugated estrogens in a double-blind placebo-controlled study: effects on menopause symptoms and bone markers. Maturitas 2003;44:S67-77. PubMed
  11. Huntley A, Ernst E. A systematic review of the safety of black cohosh. Menopause 2003;10:58-64.. DOI
  12. Cohen SM, O'Connor AM, Hart J, et al. Autoimmune hepatitis associated with the use of black cohosh: a case study. Menopause 2004;11:575-7. PubMed
  13. Vitetta L, Thomsen M, Sali A. Black cohosh and other herbal remedies associated with acute hepatitis. Med J Aust 2003;178:411-2.. PubMed
  14. Thomsen M, Vitetta L, Schmidt M, Sali A. Acute liver failure associated with the use of herbal preparations containing black cohosh. Med J Aust 2004;180:598-600.. DOI
  15. Cohen B, Schardt D. Center for Science in the Public Interest. Letter to Food and Drug Administration. Commissioner Mark McClellan, MD, PhD. March 4, 2004.

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 Black Cohosh and Diazepam Together: Common Questions

Is it safe to take Black Cohosh with Diazepam?
We do not list a known interaction between Black Cohosh and Diazepam. 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.
Do Black Cohosh and Diazepam have any of the same side effects?
Yes — our sources link each of them separately to 4 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Are Black Cohosh and Diazepam used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Black Cohosh in each. That is a conversation for your prescriber, especially if Diazepam is being adjusted to a target.
How was the Black Cohosh and Diazepam combination checked?
Interactions in our licensed database are recorded against drug classes. Diazepam is filed under 12 classifications, and Black Cohosh has documented interactions with 7 drug classes — none of Diazepam'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 Black Cohosh interact with any other medications?
Yes. Black Cohosh has 652 documented drug interactions in our database — Diazepam 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 Diazepam interact with any supplements?
Yes. Diazepam has documented interactions with 244 supplements in our database — Black Cohosh is not one of them. The Diazepam 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

Black Cohosh monograph Uses, safety profile, and every drug interaction in one place Diazepam drug information The full plain-English guide to this medication Diazepam supplement interactions Every supplement checked against Diazepam, 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 68 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Diazepam and Black Cohosh?

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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.