Sue Brenan: The heart medicine Lanoxin or its generic name is digoxin, Digitek is a common product. Lot of people around that for heart conditions and St. John's Wort actually can interact with that medicine to make it less effective. And if you are using the medicine to treat congestive heart failure that will not be good because you won't get prime, a heart function because the drug wont be able to work as well.