Millions of Americans take herbal remedies for ailments ranging from high cholesterol to depression. Though widely viewed as safe, these products can cause serious interactions in people taking prescription drugs for heart problems.
A 2010 report by Mayo Clinic researchers listed more than 25 herbal products that can be dangerous for heart patients on medication.
Which products should be on your watch list?
Check out this easy guide produced by our friends at Health.com, who worked with data from the Mayo Clinic, the National Institutes for Health and the Natural Standard Research Collaboration.
What it is: A member of the onion family, available commercially as an oil, extract, or pill (in addition to its natural state).
What it's used for: To lower total and LDL (bad) cholesterol, as well as blood pressure. Also used as a blood thinner and to combat atherosclerosis.
The risk: Garlic's blood-thinning properties can increase the risk of bleeding associated with warfarin, an anti-clotting drug commonly prescribed to people with heart-rhythm disorders, and to people who have had heart attacks or heart-valve replacements.
What it is: The extract of the leaves of the ginkgo plant (also known as the maidenhair tree), sold as a capsule or tea.
What it's used for: Ginkgo is mainly used to improve memory and prevent dementia (including Alzheimer's disease), but it has also been used to treat asthma, ringing in the ears, sexual dysfunction, and leg pain caused by poor circulation.
The risk: Increases the risk of bleeding associated with aspirin and warfarin.
What it is: A yellow-flowered plant, Hypericum perforatum, that is sold as a capsule, tea, or liquid extract.
What it's used for: Primarily used to treat depression and anxiety, St. John's wort is also used as a sedative in sleep disorders.
The risk: Affects how the body absorbs dozens of prescription medications and may diminish the efficacy of statins, beta-blockers (a class of drugs used to treat high blood pressure and heart-rhythm disorders), and calcium-channel blockers.
What it is: The dried extract of the bilberry fruit, which is very similar to the blueberry. Sold as a capsule.
What it's used for: Bilberry is used to treat problems associated with poor circulation, most notably varicose veins and venous insufficiency, in addition to diarrhea, skin problems, eyestrain, and menstrual cramps.
The risk: Bilberry may improve blood circulation, but it can also increase the risk of bleeding associated with warfarin.
What it is: A seed (often ground into a powder) that has been used since the days of ancient Egypt and is available in capsule form.
What it's used for: Fenugreek has been used for a wide range of ailments, including digestive problems, hot flashes, and a lack of breast milk. More recently, it has also been used to lower cholesterol.
The risk: Increases the risk of bleeding associated with warfarin. Fenugreek can also lower blood sugar, which can cause complications for diabetics.
What it is: The juice cartons in the supermarket, right next to the orange juice.
What it's used for: To lose weight and to promote heart health.
The risk: Grapefruit juice interferes with an enzyme that is essential for properly absorbing medications including statins and calcium-channel blockers, which intensifies the effect of those drugs. A single glass of grapefruit juice more than doubles the amount of calcium-channel blocker available to the body, research has shown.
What it is: The extract of the root of the black cohosh plant, Actaea racemosa. Sold as a capsule.
What it's used for: Black cohosh is mainly used to assuage the symptoms of menopause (hot flashes, vaginal dryness, night sweats), but it has also been used to treat joint and muscle pain.
The risk: Like St. John's wort, black cohosh may interfere with certain prescription medications, including statins, beta-blockers, and calcium-channel blockers. It also carries a risk of liver damage.
These aren't the only herbal products heart patients should be wary of.
In addition to the products pictured, angelica, capsicum, fumitory, gossypol, Irish moss, kelp, khella, lily of the valley, ephedra, night-blooming cereus, oleander, and strophanthus can all interact negatively with heart medications.
Heart patients taking medication--and everybody else, for that matter--should check with their physician before taking a dietary supplement.