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. The following guide to herbal products that heart patients should avoid was prepared using data from the report, as well as from the National Institutes for Health and the Natural Standard Research Collaboration.
Garlic

• 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.

Saw palmetto

• What it is: The fruit of the palmetto tree (a type of palm tree), available as a capsule, liquid, or tea.
• What it's used for: Primarily used to fight the urinary problems caused by an enlarged prostate gland, saw palmetto is also used to combat hair loss, chronic pelvic pain, and decreased sex drive.
• The risk: Increases the risk of bleeding associated with warfarin.