The flowers are tubular in shape, produced on a tall spike, and vary in colour with species, from purple to pink, white, and yellow.

This biennial is often grown as an ornamental plant due to its vivid flowers, which range in colour from various purple tints through pink and purely white.

[6] The term digitalis is also used for drug preparations that contain cardiac glycosides, particularly one called digoxin, extracted from various plants of this genus.

[11] Over time, folk myths obscured the literal origins of the name, insinuating that foxes wore the flowers on their paws to silence their movements as they stealthily hunted their prey.

[11] The Flora Europaea originally recognised a number of species now seen as synonyms of Digitalis purpurea, or others: D. dubia, D. leucophaea, D. micrantha and D.

[12] As of 2017, Plants of the World Online recognises the following 27 species (and a number of hybrids):[1] The first full monograph regarding this genus was written by Lindley in 1821.

[16][19] Peter Hadland Davis, an expert on the flora of Turkey, had used a different circumscription than Werner in his works, and recognised eight species in the country.

A 2016 molecular phylogenetic study into the relationships of the Turkish species in the section Globiflorae aimed to reconcile this discrepancy, finding that the classification as proposed by Davis was largely correct: Globiflorae contained as distinct species D. cariensis, D. ferruginea, D. lamarckii, D. lanata and D. nervosa, and D. trojana was subsumed at the infraspecific rank as D. lanata subsp.

He cited its use for healing wounds (both fresh and old), as a purgative, for "the King's Evil" (mycobacterial cervical lymphadenitis), for "the falling sickness" (epilepsy), and for "a scabby head".

The use of D. purpurea extract containing cardiac glycosides for the treatment of heart conditions was first described in the English-speaking medical literature by William Withering, in 1785,[24][25][26] which is considered the beginning of modern therapeutics.

[27][28] It is used to increase cardiac contractility (it is a positive inotrope) and as an antiarrhythmic agent to control the heart rate, particularly in the irregular (and often fast) atrial fibrillation.

Digoxin was approved for heart failure in 1998 under current regulations by the Food and Drug Administration on the basis of prospective, randomized study and clinical trials.

Despite its relatively recent approval by the Food and Drug Administration and the guideline recommendations, the therapeutic use of digoxin is declining in patients with heart failure—likely the result of several factors.

The main factor is the more recent introduction of several drugs shown in randomised controlled studies to improve outcomes in heart failure.

Human newborns, some animals, and patients with chronic heart failure lack well developed and fully functioning sarcoplasmic reticula and must rely on the Na/Ca exchanger to provide all or a majority of the cytoplasmic calcium required for cardiac contraction.

This is the mechanism that makes this drug a popular treatment for congestive heart failure, which is characterized by low cardiac output.

[citation needed] Depending on the species, the digitalis plant may contain several deadly physiological and chemically related cardiac and steroidal glycosides.

[42] Electrical cardioversion (to "shock" the heart) is generally not indicated in ventricular fibrillation in digitalis toxicity, as it can make the rhythm disturbance more complicated or sustained.

[47] In some instances, people have confused foxglove with the relatively harmless comfrey (Symphytum) plant, which is sometimes brewed into a tea, with fatal consequences.

According to 1981 speculation, Vincent van Gogh's "Yellow Period" may have been influenced by digitalis, because it had been proposed as a therapy to control epilepsy around this time, and there are two paintings by the artist where the plant is present.