"These products are not by themselves dangerous," says the lead author, Dr. Arshad Jahangir, a cardiologist and professor of medicine at the Mayo Clinic in Scottsdale, Arizona. "But when taken with medications for cardiovascular diseases, a relatively safe compound can become dangerous."
Herbal supplements such as ginseng, ginkgo, garlic, black cohosh, St. John's wort, hawthorn, saw palmetto, and echinacea can dilute, intensify, or exacerbate the side effects of prescription heart drugs such as blood thinners and cholesterol lowering statins, the report says.
Some supplements may also increase heart rate and blood pressure, causing potential complications in heart patients.
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Disclaimer: I am not a medical professional just an avid reader on health topics.