Foxglove (Digitalis purpurea)
While some complementary and alternative techniques have been studied scientifically, high-quality data regarding safety, effectiveness, and mechanism of action are limited or controversial for most therapies. Whenever possible, it is recommended that practitioners be licensed by a recognized professional organization that adheres to clearly published standards. In addition, before starting a new technique or engaging a practitioner, it is recommended that patients speak with their primary healthcare provider(s). Potential benefits, risks (including financial costs), and alternatives should be carefully considered. The below monograph is designed to provide historical background and an overview of clinically-oriented research, and neither advocates for or against the use of a particular therapy.
Foxglove is a common name for plants belonging to the Digitalis species, including Digitalis purpurea and Digitalis lanata. Traditional medicine has used foxglove to treat heart conditions, fevers, wounds, swelling or inflammation, sores, ulcers, cancer, edema, and infections.
Reports describe foxglove leaves as being similar to those of other species, such as Inula conyza (ploughman’s spikenard), Inula helenium (elecampane), Symphytum officinale (comfrey), Verbascum thapsus (great mullein), and Primulaceae (primrose).
Foxglove is rarely used for modern medical purposes because of its toxic effects, including nausea, vomiting, green-yellow vision, and death. Still, foxglove and other Digitalis species contain cardiac glycosides, agents known to increase the strength and speed of heartbeats, making it seemingly useful for treating certain heart disorders. However, scientific studies on the safety and efficacy of the crude herb are lacking. However, the modern drug digoxin is extracted from Digitalis lanata and is used to treat certain heart conditions. However, digoxin, unlike crude samples of foxglove, is standardized in controlled laboratory settings.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
|No available studies qualify for inclusion in the evidence table.|
*Key to grades:
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.
- Aging, allergies, anticoagulant, antimicrobial, antioxidant, antispasm, antiviral (polio), arrhythmia, arthritis, asthma, baldness, bronchitis, bruises, burns, cancer, cardiovascular disease, cataracts, common cold, constipation, delirium, dementia, dental conditions, depression, diabetes, dysmenorrhea, edema, epilepsy, expectorant, eye disorders, fever, fungal infections, headache, hemorrhage, hepatoprotection, hypercholesterolemia (high cholesterol), hyperglycemia (high blood sugar), hyperhomocysteinemia, hypertension (high blood pressure), hyperthyroidism, hypotension, immune disorders, inflammation, liver disease, malaria, mania, mental illness, mental performance, muscle tension, nausea, obesity, pain, poisoning, skin conditions, stress, surgical uses (analgesic), tuberculosis, ulcers, wound healing.
The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (18 years and older)
There is no proven safe or effective dose for digitalis in adults.
Digoxin (Lanoxin®) is a drug made from digitalis and may be taken by mouth or injected.
Children (under 18 years old)
There is no proven safe or effective dose for digitalis in children.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Avoid in people with a known allergy or sensitivity to Digitalis purpurea, members of the figwort family (Scrophulariaceae or more recently Plantaginaceae), or any of its parts.
Use cautiously in people with allergies to acetylcholine, benzoic acid, caffeic acid, chlorogenic acid, or citric acid.
Side Effects and Warnings
Note: The side effects and warnings of digoxin also apply to foxglove.
Foxglove may cause abdominal pain, abnormal heartbeats, anorexia, blocked blood flow, breathing difficulties, cancer, cardiovascular shock with a slow heartbeat rate, diarrhea, immune system abnormalities, increased urine flow, nausea, neurologic symptoms (muscle weakness and tremors, dizziness, stupor, confusion, convulsions, hallucinations, and decreased consciousness), palpitations, pregnancy difficulties, reduced levels of thyroid hormone, severe stomach and intestinal disorders, strong slow pulse, visual disturbances (flickering in the eyes, perceived flashes of light, visual halos, yellow-green vision, contracted pupils, blurred vision, seeing lights or bright spots, or blind spots in vision), and vomiting.
Drowsiness or sedation may occur. Use caution when driving or operating heavy machinery.
Use foxglove cautiously in individuals with heart damage (including those who have had a heart attack or who have heart muscle damage or stiffness in the walls of the heart, poor signaling between heart chambers, inflammation of the heart, or expanded heart chambers), heart failure, hypercalcemia (high levels of calcium), hyperdynamic states (hyperthyroidism, or overactive thyroid, hypoxia, or lack of oxygen, or arteriovenous shunt), hypocalcemia (low levels of potassium), hypokalemia (low levels of potassium), hypomagnesemia (low levels of magnesium), or kidney damage, as well as those who experience difficulty exercising or frequent hospitalizations.
Foxglove may cause increased or decreased blood pressure. Caution is advised in people taking drugs, herbs, or supplements that lower blood pressure.
Foxglove may lower blood sugar levels. Caution is advised in people with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional, including a pharmacist. Medication adjustments may be necessary.
Comfrey may be mistaken for foxglove. Caution is advised to healthcare professionals working in clinical settings in which the two can be confused.
Avoid using foxglove in patients with severely abnormal heartbeats.
Avoid using foxglove without medical supervision. Foxglove contains cardiac glycosides that are considered poisonous.
Pregnancy and Breastfeeding
There is currently a lack of scientific evidence on the use of foxglove during pregnancy or lactation.
Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.
Interactions with Drugs
Note: Agents that may interact with digoxin may also interact with foxglove.
Foxglove may increase the risk of bleeding when taken with other drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).
Foxglove may increase the amount of drowsiness caused by some drugs. Examples include benzodiazepines such as Iorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants, and alcohol. Caution is advised while driving or operating machinery.
Foxglove may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. People taking insulin or drugs for diabetes by mouth should be monitored closely by qualified healthcare professionals, including a pharmacist. Medication adjustments may be necessary.
Foxglove may affect blood pressure. Caution is advised in people taking other medications that affect blood pressure.
Because foxglove contains estrogen-like chemicals, the effects of other agents believed to have estrogen-like properties may be altered.
Many tinctures contain high levels of alcohol and may cause nausea or vomiting when taken with metronidazole (Flagyl®) or disulfiram (Antabuse®).
Foxglove may also interact with agents that affect the immune system, agents that affect the nervous system, allergy medicine, Alzheimer’s agents, antacids, antidepressants, anticancer medications, antifungals, anti-inflammatory agents (sulfasalazine in particular), antivirals, arthritis medication (sulfasalazine in particular), asthma medications, beta-blockers, birth control agents, blood vessel-widening medicines, calcium channel blockers, calcium salts, cardiac glycosides, charcoal, cholesterol-lowering agents (cholestyramine in particular), diphenoxylate, diuretics, heart medication (including heart rate-regulating agents), laxatives, macrolide antibiotics, magnesium, medicines that mimic activities of the nervous system, medicines that speed up mental or physical processes, metoclopramide, neurologic agents, pain relievers, propantheline, rifampin, skeletal muscle relaxants, skin creams, stomach ulcer medications, succinylcholine, tetracycline antibiotics, and thyroid hormones.
Interactions with Herbs and Dietary Supplements
Foxglove may increase the risk of bleeding when taken with other herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.
Foxglove may increase the amount of drowsiness caused by some herbs or supplements.
Foxglove may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need adjustments.
Foxglove may have blood pressure-lowering effects. Caution is advised in people taking herbs or supplements that lower blood pressure.
Foxglove may have estrogen-like properties. The activity of other herbs and supplements believed to have estrogen-like properties may be altered.
Foxglove may also interact with Alzheimer’s or other neurologic herbs and supplements, antacids, antiallergy herbs and supplements, anticancer herbs and supplements, antidepressants, antifungals, anti-inflammatory herbs and supplements, antivirals, asthma herbs and supplements, birth control herbs and supplements, blood vessel-widening supplements, calcium salts, cardiac glycosides, carob, charcoal, cholesterol-lowering herbs and supplements, gossypol, heart-related herbs and supplements (including heart rate-regulating herbs and supplements), herbs and supplements that affect thyroid hormones, herbs and supplements that mimic activities of the nervous system that are not controlled consciously (heartbeat, for example), herbs and supplements that speed up mental or physical processes, herbs and supplements that treat arthritis (sulfasalazine in particular), immune-suppressing herbs and supplements, laxatives (including senna and aloe), licorice, magnesium, pain-relieving herbs and supplements, potassium-depleting herbs and supplements, skin creams, and stomach ulcer herbs and supplements.
This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.
- Aikawa JK, Reardon JZ, Harms DR. Effects of digitoxin on exchangeable and tissue contents of magnesium. Proc.Soc.Exp.Biol.Med 1961;108:684-686. View Abstract
- Bessen HA. Therapeutic and toxic effects of digitalis: William Withering, 1785. J.Emerg.Med. 1986;4(3):243-248. View Abstract
- Brunton TL, Tunnicliffe FW. On the Cause of the Rise of Blood-pressure produced by Digitalis. J Physiol 10-19-1896;20(4-5):354-363. View Abstract
- dos Santos MD, Almeida MC, Lopes NP, de Souza GE. Evaluation of the anti-inflammatory, analgesic and antipyretic activities of the natural polyphenol chlorogenic acid. Biol.Pharm.Bull. 2006;29(11):2236-2240. View Abstract
- Harada T, Ohtaki E, Misu K, Sumiyoshi T, Hosoda S. Congestive heart failure caused by digitalis toxicity in an elderly man taking a licorice-containing chinese herbal laxative. Cardiology 2002;98(4):218. View Abstract
- Hobbs RE. Digoxin’s effect on mortality and hospitalization in heart failure: implications of the DIG study. Digitalis Investigation Group. Cleve.Clin.J.Med. 1997;64(5):234-237. View Abstract
- Hollman A. Drugs for atrial fibrillation. Digoxin comes from Digitalis lanata. BMJ 4-6-1996;312(7035):912. View Abstract
- Kim YW, Andrews CE, Ruth WE. Serum magnesium and cardiac arrhythmias with special reference to digitalis intoxication. Am.J Med Sci 1961;242:87-92. View Abstract
- Nahum LH. Potassium and digitalis. Conn.Med 1965;29:331-332. View Abstract
- Oishi A, Miyamoto K, Kashii S, Yoshimura N. Photopsia as a manifestation of digitalis toxicity. Can.J Ophthalmol. 2006;41(5):603-604. View Abstract
- Packer M, Gheorghiade M, Young JB, Costantini PJ, Adams KF, Cody RJ, Smith LK, Van Voorhees L, Gourley LA, Jolly MK. Withdrawal of digoxin from patients with chronic heart failure treated with angiotensin-converting-enzyme inhibitors. RADIANCE Study. N.Engl.J Med 7-1-1993;329(1):1-7. View Abstract
- Poole-Wilson PA. Digitalis: dead or alive? Cardiology 1988;75 Suppl 1:103-109. View Abstract
- Simpkiss M, Holt D. Digitalis poisoning due to the accidental ingestion of foxglove leaves. Ther.Drug Monit. 1983;5(2):217. View Abstract
- Slifman NR, Obermeyer WR, Aloi BK, Musser SM, Correll WA Jr, Cichowicz SM, Betz JM, Love LA. Contamination of botanical dietary supplements by Digitalis lanata. N.Engl.J.Med. 9-17-1998;339(12):806-811. View Abstract
- Wade OL. Digoxin 1785-1985. I. Two hundred years of digitalis. J.Clin.Hosp.Pharm. 1986;11(1):3-9. View Abstract
Copyright © 2013 Natural Standard (www.naturalstandard.com)
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.