This genus of over 20 species of biennials and perennials occurs in Europe, N Africa, and W and C Asia. Although very poisonous, foxgloves are popular as garden plants for their elegant spires of flowers. Digitalis is from the Latin digitus, "finger" because the flowers fit neatly over the fingers. Foxgloves contain cardioactive glycosides, which vary from species to species according to weather and site. Their use in the treatment of heart disease was developed by William Withering, an English physician, who in 1785 published his findings after analyzing an herbal mixture made by a Shropshire woman as a cure for dropsy (fluid retention due to heart failure). Both D. purpurea and D. lanata are grown commercially for the pharmaceutical industry, but the latter is an easier crop plant. It is a major source of digitoxin, digoxin, and gitoxin, while the glycosides in D. purpurea include digitoxin, gitoxin, gitaloxin. Digitalis grandiflora and D. lutea have similar properties, but are seldom used. Digoxin is the most rapidly excreted and leat cumulative. In pharmaceutical terms "digitalis" refers to the powdered leaf of D. purpurea are easily confused with those of comfrey. (Symphytum officinale, See, comfrey) and have caused poisoning when accidently included in herbal preparations. Digitalin is a standardized mixture of glycosides from D. purpurea, formerly used in solution for injection. Isolated glycosides are now used in preference to the whole herb, so that the dose can be more accurately monitored.

The medicinal effects of digitalis, one of our most important heart medicines, were first noted in 177 by an English doctor, William Withering. He observed that a tea made from the leaves of the foxglove plant, which contains digitalis, had diuretic properties and relieved water retention. Researchers later discovered that digitalis acted primarily on the heart, strengthening and regulating the heartbeat.

Biennial or short-lived perennial with usually one stem only, and stalkless, oblong to lanceolate, toothed leaves, to 12cm (5in) long. Cream to beige, brown-veined flowers, 3cm (1¼in) long, are produced in dense, leafy racemes in summer, followed by many-seeded capsules.

Common Name:
Other Names:
Dead Men's Bells, Digitalis, Fairy Cap, Finger Flower, Lion's Mouth, Woolly Foxglove
Botanical Name:
Digitalis lanata
Native Location:
Italy, Balkans, Hungary, Turkey.
Well-drained, rich, neutral to acid soil in partial shade. May develop crown rot and root rot in damp conditions.
By seed sown in autumn or spring. Sow on the surface, because seed needs light to germinate.
Leaves are picked before flowering and dried for commercial extraction of alkaloids.
1m (3ft)
30cm (12in)
Parts Used:
Leaves, Seed
A very bitter, diuretic herb that strengthens heart contractions.
Medicinal Uses:
Internally for heart failure and irregular heart beat. Excess causes nausea, vomiting, slow pulse, visual disturbance, anorexia, and fainting. For use by professional practitioners only.
To treat headaches, paralysis, ulcers, heart failure, asthma, and constipation.
Typical Dose:
There is no typical dose of digitalis, which today is considered obsolete because its effects vary so widely.
Possible Side Effects:
Digitalis's side effects include loss of appetite, vomiting, diarrhea, headache, and acute confusion. Digitalis contains cardiac glycosides, which can help control irregular heartbeat, reduce the backup of blood and fluid in the body, and increase blood flow through the kidneys, helping to excrete sodium and relieve swelling in body tissues. However, a buildup of cardiac glycosides can occur, especially when the herb is combined with certain medications or other herbs that contain cardiac glycosides, causing arrhythmias, abnormally slow heartbeat, heart failure, and even death.
Drug Interactions:
Taking digitalis with these drugs may increase the risk of arrhythmia (irregular heartbeat):
Albuterol, (Proventil, Ventolin)
Brimonidine, (Alphagan P, PMS-Brimonidine Tartrate)
Cilostazol, (Pletal)
Dobutamine, (Dobutrex)
Dopamine, (Intropin)
Dopexamine, (Dopacard)
Enoximone, (Perfan)
Ephedrine, (Pretz-D)
Inamrinone, (Inamrinone)
Isoetharine, (Beta-2, Bronkosol)
Isoproterenol, (Isuprel)
Metaproterenol, (Alupent)
Metaraminol, (Aramine)
Milrinone, (Primacor)
Norepinephrine, (Levophed)
Pentoxifylline, (Pentoxil, Trental)
Phenylephrine, (Neo-Synephrine Extra Strength, Vicks Sinex Nasal Spray)
Pseudoephedrine, (Dimetapp Decongestant, Sudafed)
Quinidine, (Novo-Quinidin, Quinaglute Dura-Tabs)
Sildenafil, (Viagra)
Tadalafil, (Cialis)
Terbutaline, (Brethine)
Theophylline, (Elixophyllin, Theochron)
Theophylline and Guaifenesin, (Elixophyllin-GC, Quibron)
Vardenafil, (Levitra)
Taking digitalis with these drugs may increase the risk of cardiac glycoside toxicity:
Acetazolamide, (Apo-Acetazolamide, Diamox Sequels)
Azosemide, (Diat)
Bumetanide, (Bumex, Burinex)
Chlorothiazide, (Diuril)
Chlorthalidone, (Apo-Chlorthalidone, Thalitone)
Ethacrynic Acid, (Edecrin)
Etozolin, (Elkapin)
Furosemide, (Apo-Furosemide, Lasix)
Hydrochlorothiazide, (Apo-Hydro, Microzide)
Hydroflumethiazide, (Diucardin, Saluron)
Indapamide, (Lozol, Nu-Indapamide)
Mannitol, (Osmitrol, Resectol)
Mefruside, (Baycaron)
Methazolamide, (Apo-Methazolamide, Neptazane)
Methyclothiazide, (Aquatensen, Enduron)
Metolazone, (Mykrox, Zaroxolyn)
Olmesartan and Hydrochlorothiazide, (Benicar HCT)
Polythiazide, (Renese)
Quinine, (Quinine-Odan)
Torsemide, (Demadex)
Trichlormethiazide, (Metatensin, Naqua)
Urea, (Amino-Cerv, UltraMide)
Xipamide, (Diurexan, Lumitens)
Lab Test Alterations:
May normalize arrhythmias and electrocardiogram (ECG) readings.
Disease Effects:
Overdose of digitalis may trigger irregular heartbeat, heart failure.
Supplement Interactions:
All parts are toxic if eaten. This herb and D. purpurea, especially in the form of glycosides, are subject to legal restrictions in some countries.
The Encyclopedia or Herbs by Deni Brown Copyright © 1995, 2001 pp 193-194
The Essential Herb-Drug-Vitamin Interaction Guide by Geo. T. Grossberg,MD and Barry Fox,PhD Copyright©2007 Barry Fox,PhD. Pp.186-188