Foxglove: An ornamental flower and lifesaving drug

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The plant behind heart treatments

The Medicine Hunter, Chris Kilham, travels to the New York Botanical Garden for a look at a plant called foxglove that helps heart failure patients

Native to Europe, Asia and Africa, the various species of foxglove are biennials that are beautiful to behold – as well as life-sustaining medicines. The well-known species of foxglove is also called Digitalis purpurea. The name digitalis means “finger-like.” Bearing blossoms ranging from pink, purple, white and yellow, the beautiful foxglove shrub yields beneficial cardiac glycosides known collectively as digitalin – and most notably the drugs Digoxin and Digitoxin.

In 1785 British physician William Withering was incorrectly credited with discovering the cardiovascular benefits of digitalis. That credit persists to this day. In that year his book, An account of the foxglove and some of its medical uses; with practical remarks on the dropsy, and some other diseases, was published by Swinney of Birmingham, England. Withering first learned the use of foxglove for the treatment of congestive heart failure (known at that time as dropsy) from a female herbalist from Shropshire, prompting him to experiment with the plant.

Though Withering brought use of the plant to light, its use was already well established among herbalists. In fact, Bavarian herbalist Leonhart Fuchs mentioned foxglove in his Herbal Book in 1542, and in 1552, Stirpium Tragus also mentioned the plant. Flemish physician Rembert Dodoens first prescribed the use of foxglove in 1554, and the plant was introduced into the London Pharmacopoeia in 1650. Despite this, Withering was credited with its “discovery” more than 125 years later.

To muddy the waters of nomenclature just a bit, Digoxin the drug is also commonly referred to as Digitalis. Thus, references in literature use these two names interchangeably. The drug is used to increase contractions of the heart muscle, to alleviate irregular heartbeat, and to treat congestive heart failure. Despite the efficacy of Digoxin, its use has declined, presumably due to the fact that its patent has expired, and drug companies have little financial incentive to promote the drug.

The bell-shaped blossom of foxglove combined with its toxicity have earned the plant names like “Dead Man’s Bells,” “Bloody Fingers,” “Dead Man’s Thimbles” and “Witch’s Gloves.” The shape of the blossom has ultimately earned the name foxglove, since the blossoms would fit well on the feet of a fox. This name derives from the Anglo-Saxon foxes glofa.

Like many drugs, the glycosides in foxglove must be used sparingly and with great care. Foxglove should not be drunk as an herbal tea. Its use can cause nausea, vomiting, diarrhea, dizziness, loss of appetite, jaundice and – in rare cases – death. Improper use of foxglove can cause either decreased or increased heart rate. It’s best not to attempt to self-medicate with the plant.

Foxglove the plant yields beneficial cardiac medicines that need to be employed with great care. If used on a prolonged basis, Digoxin can produce poisoning, as increasing levels of the drug build up in the blood. Nonetheless, in cases of congestive heart failure, digitalis can save lives. For this reason, the plant and its derivative drugs hold an esteemed position in the field of medicine.