Guidelines for using comfrey

External / Topical Use of comfrey

EXTERNAL use of comfrey root or leaves is NON- toxic

Based on the HMPC "Public statement on the use of herbal medicinal products containing toxic, unsaturated pyrrolizidine alkaloids (PAs)"(EMA/HMPC/572844/2009).   The acceptable daily intake is maximum 0.007 μg/kg/day for cutaneous preparations. Assessment report on Symphytum officinale L., radix EMA/HMPC/572844/2009 Page 27/27 Generally for adults the calculation is done with a body weight of 50 kg. Therefore the daily dosage would be: 0.007 μg/kg/day x 50 kg body weight = 0.35 μg/person/day for short- time use only (maximum 2 weeks). The use is restricted to intact skin.

However, combining DMSO with comfrey for external use is equivalent to taking it internally - since DMSO allows comfrey to penetrate skin through to the bloodstream.

Applying comfrey to broken skin allows comfrey PAs to enter blood stream

Using comfrey internally (i.e consuming it)

Consume comfrey for a maximum of 4 weeks;

Use Common rather than Russian comfrey, and leaves not roots (leaves contain less PAs).  Prefer comfrey source with a lower uPA (unsaturated PA) content

DAILY dose limit of 3- 5 ml liquid extract or 3- 5 g comfrey tea (in divided doses).    ~1 tsp. (1.5g) dried comfrey leaves makes 1 cup of tea.

-    Comfrey tea drinkers could be ingesting up to 5 mg of PAs per day  (i.e. 0.083 mg/ kg body weight /day).  Ingested toxic dose for humans is ~ 0.1- 10 mg PAs/kg body weight per day.    In fatal cases, total comfrey ingestion estimated 6- 167 mg/kg of body weight) and non- fatal cases of hepatic venoocclusive disease at 2- 27 mg/kg

Speijers and Egmond, as cited in Deshpande 2002b [81], p. 368)

Utilize a concurrent liver/kidney pyrrole-effect detoxifier

•   Licorice extract - Alkaline Glycerite (alkaloids not water- soluble in alkaline environment) /Glycyrrhizin - Rat study found that taking glycyrrhiza for 3 days prior to injection of powerful UPA retrorsine greatly
prevents pyrrole damage to liver
Lin 1999

•   Sulfur.   Glutathione is a powerful "in- house" antioxidant citical to detoxifying pyrrole in the liver, and glutathione's key-limiting ingredient is sulfur, particularly found in N acetylcysteine (500- 2000mg daily on empty stomach), alpha lipoic acid (300- 600mg 1- 3 x daily, also lowers blood sugar), MSM (1- 5g daily), glucosamine sulfate (1500 mg /day divided doses).

Good food sources of sulfur include egg yolks, cabbage, broccoli, cauliflower, Brussels sprouts, kale, collards, asparagus, onions, and garlic.

•   Possibly taurine and heparin

The SALE of comfrey products for INTERNAL use is illegal in the U.S. and Canada - but it is legal to purchase and grow your own comfrey in the U.S.