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Avoid with known allergy or sensitivity to black cohosh, its parts, or other members of the Ranunculaceae (buttercup or crowfoot) family.

In nature, black cohosh contains small amounts of salicylic acid (which is found in aspirin), but it is not clear how much (if any) is present in commercially available products. Black cohosh should be used cautiously in people allergic to aspirin or to other salicylates.

A minor allergic skin reaction occurred in one person taking Remixin® (40mg per tablet, Mikro-Gen, Istanbul, Turkey) in a study. Allergic reactions were also reported from a different case study. In another study, allergic eye inflammation occurred in one patient who was given either Remifemin® or Remifemin® Plus.

Side Effects and Warnings

Black cohosh is generally safe in recommended doses and when used up to one year in healthy, nonpregnant, nonbreastfeeding women. Long-term safety data are lacking.

Black cohosh has been well tolerated in breast cancer patients when taken simultaneously with tamoxifen, and in breast cancer survivors with hot flashes.

Black cohosh may cause low blood pressure. Caution is advised in people taking drugs or herbs and supplements that lower blood pressure

Use cautiously in people with a history of hormone-sensitive conditions, such as breast cancer, uterine cancer, or endometriosis (growth of endometrial tissue outside the uterus). Use cautiously in people with known seizure disorders, liver disease, or a history of stroke or disease involving blood clots. Use cautiously as a labor-inducing agent simultaneously with blue cohosh (Caulophyllum thalictroides).

Avoid in pregnant or breastfeeding women.

Avoid in patients with known allergy to black cohosh, its parts, aspirin, other salicylates, or members of the Ranunculaceae (buttercup or crowfoot) family.

Black cohosh may also cause abnormal heartbeat, abnormal vaginal discharge, altered blood pressure, bleeding disturbances, blood clots in the leg, blood vessel widening, breast cancer recurrence, breast pain, breast tenderness, chest discomfort, constipation, edema (fluid accumulation), estrogen-like effects, headache, heart problems, heaviness in the legs, hepatitis, infestation and infection, irritability, liver damage, liver failure, loss of strength, mild skin complaints, miscarriage, multiorgan damage to an infant when taken by the mother during childbirth, muscle and skeletal conditions, nausea, overgrowth of the uterine lining, rash, seizures, skin lesions, stimulation of menstrual flow, sweating, swelling, tiredness, unhappiness, upset stomach, uterine problems, vaginal bleeding, vertigo (dizziness), visual disturbances, vomiting, and weight gain.

Pregnancy and Breastfeeding

Safety during pregnancy and breastfeeding has not been established. Black cohosh may relax the muscular wall of the uterus, and some nurse-midwives in the United States use black cohosh to stimulate labor. There is one report of severe multiorgan damage in a child delivered with the aid of both black cohosh and blue cohosh (Caulophyllum thalictroides) who was not breathing at the time of birth. The child survived with permanent brain damage. However, blue cohosh is known to have effects on the heart and blood vessels and may have been responsible for these effects.

Black cohosh may also have hormonal effects, and caution is advised during breastfeeding. There is a lack of scientific evidence on the use of black cohosh during breastfeeding.

Tinctures may be ill-advised during pregnancy, due to their potentially high alcohol content.

This evidence-based monograph was prepared by The Natural Standard Research Collaboration