What is comfrey?

Comfrey is a perennial plant native to Europe and Asia. It has been used for centuries for medicinal purposes, particularly in traditional European and Chinese medicine. Comfrey has large, hairy leaves and small, bell-shaped flowers that bloom in the summer. The plant is also known as knitbone, as it was traditionally used to help heal broken bones and wounds.

How does it work for medicinal purposes?

Comfrey contains several active ingredients, including allantoin, rosmarinic acid, and tannins. These compounds have anti-inflammatory and analgesic properties that can help reduce pain and swelling. Comfrey may also help speed up the healing process by increasing cell growth and repair.

What are the active ingredients that are important for its medicinal properties?

The active ingredients in comfrey include allantoin, rosmarinic acid, and tannins.

What forms does it come in?

Comfrey is available in various forms, including teas, ointments, creams, and capsules.

When was it first used for medicinal purposes?

Comfrey has been used for medicinal purposes for centuries, dating back to ancient Greece and Rome.

What does Comfrey help with?

Comfrey is a leafy garden plant with thick, deep roots. Healers in medieval Europe used it on hurt skin, sore joints and swollen limbs. Today it is sold mostly as a cream made from the root.

• A twisted or sprained ankle
  Strong evidence — several randomised human trials against placebo, and some against diclofenac gel. Ankle sprain is the most studied use of comfrey root cream. Trials found less pain at rest and on movement, less swelling, and shorter recovery than with placebo. In some trials it did better than diclofenac gel, a standard drug gel.
  Evidence grade A · Traditional tier T3
• Back pain that has just started
  Good evidence — placebo-controlled trials in sudden upper and lower back pain. Trials tested comfrey root extract cream on sudden upper and lower back pain. People using it reported clear drops in pain compared with placebo. It is one option for people who would rather not take pain pills.
  Evidence grade B · Traditional tier T3
• Knee pain from wear-and-tear arthritis
  Good evidence — trials of comfrey extract put on arthritic joints, mostly the knee. Studies put comfrey extract on painful arthritic joints, most often the knee. People in those studies reported less pain and easier movement. Creams on the skin are generally accepted to avoid the gut upset that oral anti-inflammatory drugs can cause.
  Evidence grade B · Traditional tier T3
• Sprains and strains in other joints
  Early evidence — the trial evidence on file comes from ankle sprains only. All the sprain trials on file looked at ankles. In those trials, pain and swelling fell faster than with some standard treatments. Whether other joints respond the same way was not tested here.
  Evidence grade C · Traditional tier T3
• Bruises and blood pooled under the skin
  Long traditional use · not yet tested in trials — no human bruise trial on file; lab work on its compounds plus long traditional use. In lab work, comfrey's allantoin sped up new skin cell turnover. Its rosmarinic acid calmed inflammation in lab tests. No human bruise trial is on file here.
  Evidence grade insufficient · Traditional tier T3
• Sore, overworked muscles after hard training
  Long traditional use · not yet tested in trials — no trial of muscle soreness on file; user reports and lab work only. Athletes and active people rub comfrey cream on sore, strained muscles. Many report easing within a few days of use. No human trial of muscle soreness is on file here.
  Evidence grade insufficient · Traditional tier T3
• Minor cuts and grazes
  Long traditional use · not yet tested in trials — no comfrey wound trial on file; allantoin's role in wound care is well established. Allantoin is well established as a spur to new skin cell growth. That is why it appears in many over-the-counter wound products. Comfrey contains allantoin, but no trial of comfrey on cuts is on file here.
  Evidence grade insufficient · Traditional tier T3

What Comfrey has not been shown to do

• Comfrey has not been shown to help when swallowed; every use on file is a cream put on the skin.
• No study on file tested it on deep, open or infected wounds, only minor surface cuts and grazes.
• The joint studies on file looked mainly at the knee, so other arthritic joints are untested here.
• It has not been shown to speed recovery after exercise; that use rests on reports, not trials.
• It has not been shown to replace pain pills; the trials compared it with a drug gel on the skin.

How to read this:

The grades rate the human evidence for each use, not how strong the cream is. A means several trials in people agree. B means at least one good trial. C means small or mixed human studies. Insufficient means no human study is on file, only lab work or long use. This page reports what studies found. It is not medical advice, and it does not say comfrey will work for you. Ask your own clinician about your case, and see our page on who should avoid it.

What can it help prevent?

Comfrey has not been proven to help prevent any specific conditions or symptoms.

Which foods are rich in it?

Comfrey is not typically consumed as a food, but its leaves can be used to make tea.

What are possible side effects?

Comfrey can be toxic to the liver when taken orally, especially in high doses or for long periods. It can also cause skin irritation and allergic reactions when applied topically.

What's the recommended daily dose?

The recommended daily dose of comfrey varies depending on the form it is taken in. However, due to the potential for liver damage, it is not recommended to take comfrey supplements regularly.

How many days does it take to work?

The amount of time it takes for comfrey to work varies depending on the condition being treated and the form it is taken in. Some studies have shown that topical comfrey preparations can provide relief within a few days, while oral supplements may take longer to have an effect.

What time of day is best to take it?

There is no specific time of day that is best to take comfrey. It is typically taken as needed for pain or inflammation.

Is it best to take it with or without food?

Comfrey supplements can be taken with or without food, but it is generally recommended to take them with food to reduce the risk of gastrointestinal side effects. Topical preparations are applied directly to the affected area and do not need to be taken with food.