Background

Foxglove is a plant. Although the parts of the plant that grow above the ground can be used for medicine, foxglove is unsafe for self-medication. All parts of the plant are poisonous.

Chemicals taken from foxglove are used to make a prescription drug called digoxin. Digitalis lanata is the major source of digoxin in the US.

Foxglove is most commonly used for heart failure and fluid build up in the body (congestive heart failure or CHF) and irregular heartbeat (atrial fibrillation). But it is not safe to use for any purpose.

Safety Safety definitions

When taken by mouth: Foxglove is UNSAFE for anyone to take by mouth without the advice and care of a healthcare professional. Some people are especially sensitive to the toxic side effects of foxglove and should be extra careful to avoid use.

Foxglove can cause irregular heart function and death. Signs of foxglove poisoning include stomach upset, small eye pupils, blurred vision, strong slow pulse, nausea, vomiting, dizziness, excessive urination, fatigue, muscle weakness and tremors, stupor, confusion, convulsions, abnormal heartbeats, and death. Long-term use of foxglove can lead to symptoms of toxicity, including visual halos, yellow-green vision, and stomach upset.

Deaths have occurred when foxglove was mistaken for comfrey or borage.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Foxglove is UNSAFE when taken by mouth for self-medication. Do not use.

Children: Taking foxglove by mouth is LIKELY UNSAFE for children.

Heart disease: Although foxglove is effective for some heart conditions, it is too dangerous for people to use on their own. Heart disease needs to be diagnosed, treated, and monitored by a healthcare professional.

Kidney disease: People with kidney problems may not clear foxglove from their system very well. This can increase the chance of foxglove build-up and poisoning.

Effectiveness

Dosing & administration

The appropriate dose of foxglove depends on several factors such as the user's age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for foxglove. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.

Interactions with pharmaceuticals

Antibiotics (Macrolide antibiotics)

Interaction Rating=Moderate Be cautious with this combination.

Foxglove can affect the heart. Some antibiotics might increase how much foxglove the body absorbs. Increasing how much foxglove the body absorbs might increase the effects and side effects of foxglove.

Some antibiotics called macrolide antibiotics include erythromycin, azithromycin, and clarithromycin.

Antibiotics (Tetracycline antibiotics)

Interaction Rating=Moderate Be cautious with this combination.

Taking some antibiotics called tetracyclines with foxglove might increase the chance of side effects from foxglove.

Some tetracyclines include demeclocycline (Declomycin), minocycline (Minocin), and tetracycline (Achromycin).

Digoxin (Lanoxin)

Interaction Rating=Major Do not take this combination.

Digoxin (Lanoxin) helps the heart beat more strongly. Foxglove also seems to affect the heart. Taking foxglove along with digoxin can increase the effects of digoxin and increase the risk of side effects. Do not take foxglove if you are taking digoxin (Lanoxin) without talking to your healthcare professional.

Quinine

Interaction Rating=Major Do not take this combination.

Foxglove can affect the heart. Quinine can also affect the heart. Taking quinine along with foxglove might cause serious heart problems.

Stimulant laxatives

Interaction Rating=Moderate Be cautious with this combination.

Foxglove can affect the heart. The heart uses potassium. Laxatives called stimulant laxatives can decrease potassium levels in the body. Low potassium levels can increase the chance of side effects from foxglove.

Some stimulant laxatives include bisacodyl (Correctol, Dulcolax), cascara, castor oil (Purge), senna (Senokot), and others.

Water pills (Diuretic drugs)

Interaction Rating=Moderate Be cautious with this combination.

Foxglove might affect the heart. "Water pills" can decrease potassium in the body. Low potassium levels can also affect the heart and increase the risk of side effects from foxglove.

Some "water pills" that can deplete potassium include chlorothiazide (Diuril), chlorthalidone (Thalitone), furosemide (Lasix), hydrochlorothiazide (HCTZ, HydroDiuril, Microzide), and others.

Interactions with herbs & supplements

Herbs that contain cardiac glycosides: Foxglove contains cardiac glycosides, which are chemicals that can affect the heart. Using foxglove along with other herbs that also contain cardiac glycosides can increase the risk of harming the heart. Other herbs that contain cardiac glycosides include black hellebore, Canadian hemp roots, hedge mustard, figwort, lily of the valley roots, motherwort, oleander leaf, pheasant's eye plant, pleurisy root, squill bulb leaf scales, and strophanthus seeds.
Horsetail: Foxglove contains cardiac glycosides, which are chemicals that can affect the heart. Using horsetail with a cardiac glycoside-containing herb such as foxglove increases the risk of making potassium levels drop so low that there are very serious health effects.
Licorice: Foxglove contains cardiac glycosides, which are chemicals that can affect the heart. Using licorice with a cardiac glycoside-containing herb such as foxglove increases the risk of making potassium levels drop so low that there are very serious health effects.
Stimulant laxative herbs: Foxglove contains cardiac glycosides, which are chemicals that can affect the heart. Using stimulant laxative herbs with a cardiac glycoside-containing herb such as foxglove increases the risk of making potassium levels drop so low that there are very serious health effects. Stimulant laxative herbs include aloe, alder buckthorn, black root, blue flag, butternut bark, colocynth, European buckthorn, fo ti, gamboge, gossypol, greater bindweed, jalap, manna, Mexican scammony root, rhubarb, senna, and yellow dock.

Interactions with foods

There are no known interactions with foods.

Action

Foxglove contains chemicals from which the prescription medication digoxin (Lanoxin) is made. These chemicals can increase the strength of heart muscle contractions, change heart rate, and increase heart blood output.