Black Cohosh - Premarin (Conjugated Estrogens) Interaction
Herbal: Black Cohosh
Also Known As: Actaea racemosa, Baie d'actée, Baneberry, Black Aristolochiaceae, Black Snakeroot, Bugbane, Bugwort, Cimicaire à grappes, Cimicifuga, Cimicifuge, Cohosh Negro, Cohosh Noir, Cytise
Drug: Conjugated Estrogens
Brand names:
Premarin, Cenestin, Enjuvia, Premarin Vaginal Cream
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Jun 15, 2025
Interaction Details
Conjugated Estrogens is classified as belonging to the following category: Estrogens
Theoretically, black cohosh may alter the effects of estrogen therapy.
Some research suggests that black cohosh has estrogenic effects. This may enhance or inhibit the effects of estrogen therapy.
Interaction Rating
Likelihood of Occurrence
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
References
- 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.
- Seidlova-Wuttke D, Hesse O, Jarry H, et al. Evidence for selective estrogen receptor modulator activity in a black cohosh (Cimicifuga racemosa) extract: comparison with estradiol-17beta. Eur J Endocrinol 2003;149:351-62.
- Dugoua JJ, Seely D, Perri D, et al. Safety and efficacy of black cohosh (cimicifuga racemosa) during pregnancy and lactation. Can J Clin Pharmacol 2006;13:e257-61.
- Nuntanakorn, P., Jiang, B., Einbond, L. S., Yang, H., Kronenberg, F., Weinstein, I. B., and Kennelly, E. J. Polyphenolic constituents of Actaea racemosa. J Nat Prod 2006;69(3):314-318.
Black Cohosh Overview
Black cohosh (Actaea racemosa) is a perennial plant native to North America and is sometimes referred to as "black snakeroot" or "bugbane". Black cohosh is often taken as a supplement to help with menopause symptoms, such as hot flashes, night sweats, and mood changes. It is also sometimes used to help with premenstrual syndrome (PMS) and other menstrual issues. Black cohosh supplements are typically standardized for their triterpene glycoside content.
Conjugated Estrogens Overview
-
The estradiol cypionate and estradiol valerate forms of estrogen injection are used to treat hot flushes (hot flashes; sudden strong feelings of heat and sweating) and/or vaginal dryness, itching, and burning in women who are experiencing menopause (change of life; the end of monthly menstrual periods). However, women who need a medication only to treat vaginal dryness, itching, or burning should consider a different treatment. These forms of estrogen injection are also sometimes used to treat the symptoms of low estrogen in young women who do not produce enough estrogen naturally. The estradiol valerate form of estrogen injection is also sometimes used to relieve the symptoms of certain types of prostate (a male reproductive organ) cancer. The conjugated estrogens form of estrogen injection is used to treat abnormal vaginal bleeding that a doctor has decided is caused only by a problem with the amounts of certain hormones in the body. Estrogen injection is in a class of medications called hormones. It works by replacing estrogen that is normally produced by the body.
Black Cohosh - More Interactions
Black Cohosh interacts with 622 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
| Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
| Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
| Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
| Unknown | No interactions have been reported or no interaction data is currently available. |
Return to the main supplement interaction checker page
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
Drug descriptions are provided by MedlinePlus.
Ask A Pharmacist About Your Herbal Questions!
Dr. Brian Staiger, PharmD
In addition to being a clinical pharmacist specializing in pharmacotherapy, Dr. Brian Staiger is a registered herbalist through the American Herbalist Guild. He has combined his passion for pharmacy practice with the study of medical ethnobotany to improve patient care. Feel free to reach out about any of your herbal or medication questions!
Ask A Pharmacist