Wonder Herb or Toxin?


Comfrey is not only great for the garden but also has a lot of medicinal properties. This plant is also a highly controversial herb. Besides plantain herb, comfrey happens to be one of my favorite herbs to grow and use.

Personal Experience with Comfrey

Several years ago, during a snow storm, my mother fell and broke a rib. Her job at the time required a lot of stocking and heavy lifting. She had no insurance and could not afford to miss any work. She went to the doctor just to hear him say, ‘There is nothing we can do. Take it easy and it will take about three months to heal. Needless to say, this wasn’t any help.

I asked her if she wanted to try a natural approach since the doctor had already said he couldn’t help. She agreed, so I turned to comfrey.

That night, before she went to bed, I took about a 2 TBS of dried comfrey, placed it in a small pot and covered it with a little water. Bringing it to a slow simmer, I then removed it from the heat and let it steep about 10 minutes.  I then placed this poultice into some gauze to hold it together, laid it on her rib, and then rapped a bandage around her to hold it in place for the night. She had to sleep in a half-way upright position due to the pain of breathing with a broken rib. We did this every night. After about 7 days, she reported that even though she could still feel a little bit of popping, the pain was gone. That was great news because all this time, she was STILL STOCKING heavy items at work. We continued in this manner and at around the two week mark, she no longer felt any popping.  After applying the poultice every night for three weeks, we discontinued it. She never missed a day of work and the bone had ‘knitted’ back together using this ‘knitbone’ plant.

Two years later

During an ice storm, she once again slipped and fell and broke a rib … another one … on the other side. This time she didn’t waste time and money going to the doctor just to have them say ‘sorry, can’t help you’. She asked for the poultice instead. This time we were not as vigilant in the application. It was applied sporadically, not nightly. It also took longer for the bone to heal itself. Instead of only two weeks (we went a week longer the first time just to be sure), it took about six weeks. This was still far less than the three months the doctor had stated.


Comfrey has been used for centuries for many different aliments, including by the North Americans Indians who recognized its value. They referred to it as the ‘knitbone’ plant.  However, by the 1970’s, rumors about this powerful herb lead to it being outlawed for medicinal use in some countries. Because of its relationship to a plant known to have a chemical which is toxic to the liver, it was assumed that comfrey also did. Clinical tests and trails have been done on comfrey. The roots do in fact have some of this chemical and it is recommended for external use only. The leaves however, vary. The results showed the young spring leaves did have trace amounts while the more mature summer leaves showed no trace amounts. This is why most countries at this time allow the internal use of comfrey leaves, including capsules and teas. Below I will post links you can refer to, which include some medical websites and clinical trials.


Comfrey has long tap roots which grow deep into the subsoil. This allows it to harvest many minerals that other garden plants don’t have access to. Using the leaves as mulch around other plants can greatly benefits them. I love throwing handfuls of the leaves in my compost pile. It’s amazing at how much faster the pile composts by just a few leaves.

Parts Used:

roots externally only, leaves externally and internally



Pyrrolizidine alkaloids


Symlandine (investigations revealed this not to be found in the dried leaves)


Indications/ Benefits:

speeds cell replication for quickly healing wounds, stomach ulcers, IBS, sprains, broken bones, ligaments, respiratory conditions, bronchitis, anemia, bruises, cuts, inflamed skin and rashes, aching joints,

Cautions/ Interactions/ Side Effects:

No known drug interactions are known at this time

Caution is suggested when using internally in combination with any medication or herb which is hard on the liver

This herb has the potential to be a genotoxic carcinogen, however the risks seem to be low. Do not use internally for long periods of time and include liver supporting herbs and food in your diet.


Dose/ Preparations:

tincture (1:5 in 60%) 2.5 – 5 ml (1/2 to 1 teaspoon) in single dose: or 20 drops in hot water up to 5 times per day

infusion: 1-3 tsp dried herb per cup boiling water taken one to three times per day

poultice for external wounds: lightly simmer amount of herb needed to cover wound for 5-10 minutes, strain but allow to stay moist, apply to wound and cover BE SURE WOUND IS VERY CLEAN

How to Grow:

  • sow seeds shallowly outside in early spring
  • or make root divisions in late fall or early spring
  • may be considered a weed and thus hardy
  • space about 2-3 foot apart
  • divide every few years to refresh growth
  • harvest roots in fall
  • harvest the mature summer leaves, not early spring leaves
  • dehydrate leaves at low temperature or hang in bunches out of the sun

Side Note

Because there is a slim chance that comfrey could put strain on the liver, every time I make a tea with it, I use milk thistle. Milk thistle is a very good herb for liver support.

Also, because this can speed up healing, it is possible to trap dirt and infection inside the skin. Be sure to clean the wound VERY well before using.

History/ Folklore:

European folk herbalism has indicated it has a reputed anticancer action

Footnotes/ Resources:

Michalak, Patricia S. Rodales’s Successful Organic Gardening Herbs.  Pennsylvania: Rodale Press, 1993. Print.

Chevallier FNIMH, Andrew. Encyclopedia of Herbal Medicine. New York: Dorling Kindersley, 2000. Print.

Hoffmann FNIMH, David. Medical Herbalism The Science and Practice of Herbal Medicine. Rochester: Healing Arts Press, 2003. Print.

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