Today I'm going to answer a question which I get every now and then:
"Are comfrey and/or coltsfoot safe to use? There have been alkaloids in both which are identified as liver toxins/carcinogens and they have been taken off the shelves in this and other countries. Yet there is a long history of both plants being used medicinally. I am confused...are they safe or harmful?"
Ok, so, comfrey (Symphytum officinale) has a thousands-year long history as one of (if not THE) most useful herb in Western botanical medicine. Coltsfoot (Tussilago farfara) has a similarly long history, used in both the East and the West to treat coughs.
Why are they so effective? asks modern scientific research/medicine. Let's take them apart and see! answers modern scientific research/medicine.
Instead of looking at the plants as a whole, science took it apart to find out what is the active ingredient. In both cases they isolated a specific alkaloid - pyrrolizidine - in the plants. Upon further research, when this alkaloid was fed to rats in large amounts, the rats developed liver cancer.
Now, please don't downplay the fact that comfrey and coltsfoot have constituents which can be harmful to the liver. In this day and age with the Standard American Diet (which has enveloped most the western world) of alcohol, greasy fast food, sugar, packaged food, and animal protein the last thing our livers need are more toxins to deal with. So yes, maybe it is best to avoid these herbs and reach for something else.
However, T. Colin Campbell in his book The China Study (please watch Forks Over Knives for a GREAT explanation of this...it's available as a "watch now" on netflix) discusses a study featuring another liver toxin: aflotoxin. This known liver toxin caused liver cancer in rats, yet when they fed the rats a diet of less than 5% animal protein the cancer would switch off!
So maybe there is more to getting liver cancer than eating something which may have liver toxins in it? Cancer is a relatively new disease, definitely a new epidemic, and our modern diet is a definite contributor. These plants have been eaten and used as herbs and medicine for thousands of years.
So, should you take comfrey or coltsfoot as herbal remedies? It's ultimately up to you. How much animal protein do you eat? How much of a Standard American Diet do you have?
My article Coltsfoot Cures Coughs Naturally shows how coltsfoot has been used historically in Eastern and Western medicine. But google "coltsfoot liver toxin" for the other side of the story. Similarly with comfrey. (I've included a link to the findings for toxicity for both herbs below.)
What do I do? I eat comfrey as a green. It grows in my yard and I add it to juice and smoothies. I love it. I also dry the leaves to make a tea and I make oil and salve from the leaves and root. I also use homeopathic symphytum (which is comfrey) as a bone healing remedy. I am more concerned with the pollution in the air and the water and the contaminants in our food (especially genetic engineering). But that is just me.
Also, using the herbs externally as oils and salves has always been considered safe, as has homeopathic use. Comfrey is very commonly used externally.
Safety Issues Affecting Herbs: Pyrrolizidine Alkaloids
Coltsfoot Cure Coughs Naturally
The China Study
Forks Over Knives (movie)
David and Melissa Sokulski, L.Acs.
The Birch Center for Acupuncture
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