There is good evidence that St John's wort can reduce the levels of
digoxin by roughly 30%.
Digoxin toxicity has occurred in a patient taking
digoxin when he stopped taking St John's wort.
Digoxin levels should be well monitored if St John's wort is either started or stopped and appropriate
digoxin dosage adjustments made if necessary. The recommendation of the CSM in the UK is that St John's wort should not be taken by patients taking
digoxin.