En Español (Spanish Version) Symphytum officinale
Principal Proposed Uses
Other Proposed Uses
Broken Bones;Bruises; Varicose Veins ;Open wounds (Not Recommended)
Note: the use of oral comfrey and topical comfrey over open wounds should be avoided.
Comfrey is a high-yielding leafy green plant that has been used for centuries as a feed crop for animals and a medicine for humans. However, in 2001, it was removed as an oral dietary supplement from the U.S. market, and, soon afterwards, as a commercial animal food source. These actions were taken because comfrey contains dangerous levels of toxic pyrrolizidine alkaloids and its use has led to severe liver injury and death.
Traditionally, oral or topical use of comfrey was said to help bones heal more rapidly, and this is the origin of its Latin name Symphytum (drawing together). It was also used orally for the treatment of digestive and lung problems. Topical comfrey creams have been used to treat minor wounds, bruises, sprains, and varicose veins.
Comfrey is commonly included in salves and creams that also contain such herbs as aloe, goldenseal, calendula, and vitamin E. Such preparations are marketed for treatment ofminor wounds. However, forsafety reasons, comfrey should not be applied to broken skin. Therefore, it should not be used for the treatment of lacerations or abrasions (cuts and scrapes).
There is some evidence that topical comfrey might be useful in the treatment of various conditions involving pain in the joints or muscles where skin is unbroken. Safety, however, does remain a concern.
In a double-blind, placebo-controlled study of 142 people with acute ankle sprain, use of comfrey cream for 8 days significantly enhanced rate of recovery.1Comfrey proved more effective than placebo in measurements of pain, swelling, and mobility. More modest benefits were seen in another double-blind trial, this one enrolling 203 people with ankle sprain and comparing a high-comfrey to a low-comfrey product.2
Another double-blind, placebo-controlled study, this one enrolling 215 people, found comfrey cream helpful for treatment of back pain.13 Finally, in a 3-week double-blind study of 220 people with osteoarthritisof the knee, comfrey cream reduced symptoms significantly more than a placebo cream.14
In a recent, well-designed trial, two concentrations of comfrey creams were evaluated for the treatment of fresh abrasions among 278 patients (almost a quarter of whom were under age 20).15 The higher concentration cream (10%) contained 10 times more comfrey than the low-concentration cream (considered the reference or placebo cream). The 10% comfrey cream led to significantly faster wound healing than the reference cream after 2 to 3 days of application. Although the researchers reported no adverse effects in either group, the use of comfrey has been associated with severe, even life-threatening toxic effects when used orally, and its use over open wounds must be undertaken with extreme caution.
Additional studies, generally of lower quality, suggest possible benefit for shoulder tendonitis and knee injuries.3
The active ingredients in comfrey are not known, but may include rosmaric acid, choline, and allantoin.
Last reviewedAugust 2013by EBSCO CAM Review Board
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.