Comfrey

What other names is Comfrey known by?

Ass Ear, Black Root, Blackwort, Bruisewort, Common Comfrey, Consolidae Radix, Consound, Consoude, Consoude Officinale, Consuelda, Grande Consoude, Gum Plant, Healing Herb, Herbe aux Charpentiers, Herbe à la Coupure, Knitback, Knitbone, Langue-de-Vache, Oreille d'Âne, Salsify, Slippery Root, Symphytum officinale, Wallwort.

What is Comfrey?

Comfrey is a plant. Even though this plant contains poisonous chemicals called pyrrolizidine alkaloids (PAs), the leaf, root, and root-like stem (rhizome) are used to make medicine. The amount of PAs found in comfrey changes according to the time of harvesting and the age of the plant. The roots have 10 times higher amounts of PAs than the leaves. Some products labeled "common comfrey" or Symphytum officinale actually contain the more poisonous "prickly comfrey" (Symphytum asperum) or "Russian comfrey" (Symphytum x uplandicum) species.

Comfrey is used as a tea for upset stomach, ulcers, heavy menstrual periods, diarrhea, bloody urine, persistent cough, painful breathing (pleuritis), bronchitis, cancer, and chest pain (angina). It is also used as a gargle for gum disease and sore throat.

Comfrey is applied to the skin for ulcers, wounds, joint inflammation, bruises, rheumatoid arthritis, swollen veins (phlebitis), gout, and fractures.

Possibly Effective for...

  • Back pain. Applying a specific comfrey extract (Kytta-Salbe f by Merck Selbstmedikation GmbH) to the affected area for 5 days seems to decrease lower or upper back pain.
  • Osteoarthritis. Applying a specific comfrey extract (Kytta-Salbe f) to the affected area for 3 weeks or applying a specific cream containing comfrey extract, tannic acid, Aloe vera gel, eucalyptus oil, and frankincense oil (4Jointz) to the affected are for 12 weeks seems to decrease pain in people with knee osteoarthritis.
  • Sprains. Early research suggests that applying comfrey ointment to the affected area for up to 2 weeks improves mobility, decreases pain, and reduces tenderness and swelling of sprains. The effect of comfrey ointment in relieving pain and reducing swelling seems to be comparable to the effects of diclofenac gel. Most of the studies have used a specific comfrey ointment that is low in pyrrolizidine alkaloids (Kytta-Salbe f).

Insufficient Evidence to Rate Effectiveness for...

  • Bruises. Early research suggests that applying comfrey directly to the skin for 2 weeks might decrease pain and tenderness of bruises.
  • Skin ulcers.
  • Wounds.
  • Broken bones.
  • Heavy menstrual periods.
  • Diarrhea.
  • Cough.
  • Sore throat.
  • Gum disease.
  • Joint pain.
  • Chest pain.
  • Cancer.
  • Inflammation (pain and swelling).
  • Other conditions.
More evidence is needed to rate the effectiveness of comfrey for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).


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