8 mins read

Overview: Foxglove is a plant called Digitalis purpurea. The leaves of the plant contain chemicals called cardiac glycosides, which have effects on the heart. These chemicals can cause many side effects, including changes in heart rhythm, loss of appetite, nausea, vomiting, diarrhea, stomach pain, blurry vision, headache, weakness, dizziness, confusion, anxiety, and depression. Foxglove can also be poisonous, even when taken in very small amounts. Speak with a health care provider before using foxglove for any reason.

Uses

What is foxglove used for?

In the past, foxglove (Digitalis purpurea) has been used to help with certain heart problems and weight loss. But this plant can cause serious side effects, and its use is now considered unsafe.

Note: The FDA has not reviewed foxglove for safety and effectiveness. Learn more about dietary supplements here.

How does foxglove work (mechanism of action)?

Foxglove is a plant called Digitalis purpurea. Products that contain foxglove are made from the leaves of the plant. These leaves contain chemicals, called cardiac glycosides, that can cause serious side effects when taken by mouth. Foxglove is not the same as Chinese foxglove (Rehmannia glutinosa). These are different plants that have very different effects in the body.

Cardiac glycosides can change the way that your heart functions. When used correctly and at the right dose, they can help manage certain heart conditions. In fact, this is how digoxin was discovered. Digoxin is available in the U.S. as a prescription medicine for heart failure and atrial fibrillation.

But cardiac glycosides can also cause serious side effects. Even low doses of prescription digoxin can become toxic. Herbal products, such as foxglove, naturally contain different amounts of many different chemicals. The amounts of each chemical in a specific foxglove product may vary. As a result, foxglove products can be unsafe, or even poisonous, at usual doses. See the Side Effects section for more information.

How should I store foxglove?

You should store foxglove according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of foxglove?

The most common side effects of foxglove are listed below. These side effects may vary depending on the dose you are taking or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.

  • Heart problems, including changes in heart rate or rhythm (see below)
  • Loss of appetite
  • Nausea, vomiting, or diarrhea
  • Stomach pain or intestine problems
  • Blurry vision or yellow/green vision
  • Headache
  • Weakness
  • Dizziness
  • Confusion
  • Anxiety, depression, or hallucinations
  • Rash

There may be other side effects of foxglove that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of foxglove?

While less common, the most serious side effects of foxglove are described below, along with what to do if they happen.

Severe Allergic Reactions. Foxglove may cause allergic reactions, which can be serious. Stop taking foxglove and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching or skin rash
  • Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Heart Rate or Rhythm Changes. Foxglove contains chemicals that can make your heart beat slower than normal (bradycardia). It may also cause heart rhythm problems that can lead to an irregular heartbeat and fainting. In rare cases, this may cause the heart to suddenly stop beating (cardiac arrest). Some people have a higher risk of this, including people who have heart disease or who take medicines that affect the heart. To avoid these problems, it is best not to take foxglove. If you are taking foxglove and have any of the following signs or symptoms of heart rate or rhythm changes, seek medical help right away.

  • Chest pain
  • Shortness of breath
  • Feeling dizzy or lightheaded or fainting
  • Changes in your heart rate or rhythm, such as fast, slow, pounding, or skipping heartbeat
  • Confusion
  • Feeling weak or easily tired

Cardiac Glycoside Toxicity. Foxglove contains chemicals called cardiac glycosides, including digoxin. Having too much digoxin in your body may cause digoxin toxicity. Since foxglove contains unknown amounts of digoxin, it is best to avoid using foxglove entirely. If you are taking foxglove and have any symptoms of digoxin toxicity, seek medical help right away.

  • Loss of appetite
  • Nausea or vomiting
  • Persistent diarrhea
  • Confusion 
  • Weakness
  • Changes in vision
  • Abnormal heart rhythm (also called arrhythmia)
  • Fast or slow heartbeat

Foxglove Poisoning. Foxglove contains chemicals that can be poisonous. Foxglove poisoning can happen when the plant is eaten or when foxglove dietary supplements are taken by mouth. Due to the risk of serious side effects, it is best to avoid foxglove entirely. But some people have had foxglove poisoning after confusing it for another, nontoxic plant. If you have any of the following symptoms of foxglove poisoning, seek medical help right away.

  • Changes in your heart rate or rhythm, such as fast, slow, pounding, or skipping heartbeat
  • Chest pain
  • Severe nausea and vomiting
  • Severe abdominal pain
  • Severe weakness or exhaustion

Warnings & Precautions

Who should not use foxglove?

Allergies to Ingredients. People who are allergic to any of the following should not take foxglove.

  • Digitalis
  • Digitalis purpurea
  • Digitoxin
  • Digoxin
  • Foxglove
  • Any of the ingredients in the specific product

Ask your health care provider if you are not sure what ingredients are in a foxglove product.

Irregular Heart Rhythm. If you have an abnormal heart rhythm, you should not use foxglove.

What should I know about foxglove before using it?

Foxglove is a plant that is sometimes available as a dietary supplement, although it is considered generally unsafe. In the U.S., the FDA requires that foxglove products carry a warning regarding the dangers of use, including potentially deadly heart rhythm problems or other adverse effects. Foxglove cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.

Keep foxglove out of the reach of children and pets. Foxglove can be poisonous.

Foxglove can affect your alertness or coordination, as well as your blood pressure and heart rate. Due to these and other side effects, it is best to avoid the use of foxglove entirely. If you are taking a foxglove product, do not drive or do other activities that require alertness or coordination until you know how it affects you.

Herbal products, such as foxglove, naturally contain many different chemicals. The amount of each chemical in a specific foxglove product can change for many reasons, including the area where the plant was grown, the weather during growth, the time of year when it was harvested, and the way that the plant was processed after it was harvested. If you switch to a new bottle or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.

The FDA has not tested foxglove products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using foxglove?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. Also tell them if you have an upcoming surgery planned. Sharing this information will help your health care provider know if this or other supplements are right for you.

In particular, make sure that you discuss any of the following.

Medical Procedures. Tell your health care provider that you are taking foxglove if you are undergoing any medical procedures, including a medical procedure called electrical cardioversion.

Other Current and Past Health Conditions. Tell your health care provider if you have or have had any of the following.

Other Medicines and Supplements. Foxglove may interact with other medicines and supplements. Before taking foxglove, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how foxglove could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. Certain chemicals in foxglove, such as digoxin, pass into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. 

Interactions

Does foxglove interact with foods or drinks?

There are no known interactions between foxglove and foods or drinks.

It is unknown if drinking alcohol will affect foxglove. The risk of dizziness, blurred vision, and confusion may be increased if you drink alcohol while taking foxglove.

Does foxglove interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking foxglove.

  • A medicine used to control your heart rate or rhythm (antiarrhythmic), such as dofetilide (Tikosyn) or sotalol (Betapace, Sorine, others)
  • A beta-blocker, such as atenolol (Tenormin), metoprolol (Lopressor, Toprol XL, and others), or propranolol (Inderal LA, Innopran XL), which is a medicine that may be used for certain heart conditions or to lower blood pressure
  • A calcium channel blocker, such as diltiazem (Cardizem CD and others) or verapamil (Verelan, Verelan PM), which is a medicine used for high blood pressure or other conditions
  • Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure

The interactions between foxglove and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with foxglove is incomplete. Always check with your health care provider before taking foxglove with any medicines.

Overdose/Missed Dose

What should I do if I accidentally use too much foxglove?

If you or someone else has used too much foxglove, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Foxglove contains chemicals that can cause serious side effects, even in low doses. It is best to avoid the use of foxglove entirely.