Foxglove is the plant source of digitalis compounds used to treat some heart conditions.
Digitalis refers to a group of cardiac glycosides originally obtained from foxgloves, especially Digitalis purpurea and Digitalis lanata. These compounds include digoxin and digitoxin, medicines that can affect heart contraction and electrical activity.
The medical importance of foxglove was established in the eighteenth century through the work of English physician William Withering. He studied a traditional herbal remedy and published observations on its use for dropsy, a historical term often associated with fluid retention from heart failure.
Foxgloves are also poisonous plants. The therapeutic dose is close enough to the toxic dose that digitalis medicines require careful medical supervision. Digitalis is therefore not a safe home remedy, and eating foxglove leaves or flowers can cause serious poisoning.