The therapeutic effects of extracts of foxglove Digitalis purpurea, which are used to strengthen heartbeat in patients suffering from heart failure, were first described by the doctor and botanist William Withering in 1775.
After a herbalist served him with tea that made his heart race, Withering was curious to know which of its 20 herbal ingredients was responsible, so he tested each separately on himself.
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He identified foxglove leaves as the stimulant and used them with great success to treat patients with congestive heart failure, known as dropsy in his day. His discovery, and his careful clinical testing of the herb, brought him fame and fortune.
The most active compounds in the plant were subsequently identified as digitoxin and digoxin, and the latter is still used to treat heart ailments.
Like many herbal extracts it is potentially lethal but therapeutic in carefully controlled low doses. The drugs are still extracted from foxglove plants, though D. lanata is now the source, rather than our native foxglove, because it contains higher concentrations of the active substances.
