In one older woman, stopping black cohosh was followed by her unusually slow heart rate improving without needing a pacemaker.
In one older woman, stopping black cohosh was followed by her unusually slow heart rate improving without needing a pacemaker.
Black cohosh is an herbal supplement many women use for hot flashes and other menopausal symptoms. This report describes a 76-year-old woman who came to the emergency room after briefly fainting while seated. Her heart rate was low (in the 40s–50s), and heart monitoring showed it sometimes dropped into the 30s at night.
Doctors checked for other common causes of fainting and slow heart rate, including heart damage, blocked heart arteries, and a blood clot in the lungs. Testing did not show those problems, and her thyroid level and other routine labs were normal. During her hospital stay, she did not continue black cohosh, and her heart rate gradually returned to the 60s. At follow-up, she had stopped black cohosh and reported no further palpitations.
Why this matters for seniors: herbal supplements can act like medicines in the body and may affect the heart—especially in older adults and those with heart or blood pressure conditions. New dizziness, fainting, or a slow pulse should be checked right away.
Use the full description to understand the study design, methods, and the limits of the findings.
A closer look at what this report found and what it may mean for you:
Study design (in simple terms): This was a single-patient “case report.” Doctors carefully described one woman’s symptoms, testing, hospital monitoring, and what happened after black cohosh was stopped.
Key findings (with numbers): Her heart rate was 51 beats/min on arrival, 47 on ECG, and heart monitoring showed drops into the 30s for up to about one minute (mostly at night). After black cohosh was held, her baseline heart rate improved into the 60s and she did not need a pacemaker.
Important caveats: Because this is only one case, it cannot prove black cohosh always causes slow heart rate. Other factors (age, other medications, and overall health) may have contributed. Still, the timing—improvement after stopping the supplement—raises concern.
Practical implications for daily life: If you take black cohosh (or any supplement), keep a current list for every medical visit. Seek urgent care for fainting, new dizziness, unusual fatigue, chest discomfort, or a very slow pulse. Be extra cautious if you have heart disease, a history of fainting, or take blood pressure/heart medicines.
Always talk with your healthcare provider before starting, stopping, or restarting black cohosh—especially if you’ve had dizziness, fainting, palpitations, or any heart rhythm concerns.
Open the original publication for the complete methods, outcomes, and source material.
Methodologically, this is low-level evidence because it is a single case report. While the temporal relationship (bradycardia observed while taking black cohosh and improvement after discontinuation) can raise a safety signal, the design cannot rule out alternative explanations or quantify risk. For adults 60+, the clinical narrative is relevant and may appropriately prompt caution and clinician awareness, but it should not be treated as proof of causation or used to estimate how often this occurs. Stronger evidence would require well-characterized case series, pharmacovigilance analyses, or controlled observational studies with careful adjustment for comorbidities and concomitant medications, plus verification of supplement composition.
| Category | Score | Rating |
|---|---|---|
| Study Design / Evidence Level | 2.5/10 | |
| Bias & Methods | 3.0/10 | |
| Statistical Integrity | 1.0/10 | |
| Transparency | 6.5/10 | |
| Conflict of Interest Disclosure | 6.0/10 | |
| Replication / External Validation | 2.0/10 | |
| Relevance to Seniors | 8.5/10 | |
| Journal Quality | 7.0/10 |
Key limitations for senior-focused decision-making: (1) n=1 and no comparator; (2) potential confounding from age-related conduction disease and other exposures; (3) supplement heterogeneity—product identity, dose, duration, and independent testing for adulterants/contaminants are often missing in case reports; (4) outcomes may be influenced by in-hospital monitoring conditions and medication changes. Best use: hypothesis generation and safety awareness rather than efficacy/risk quantification.
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