Comfrey, scientifically known as Symphytum officinale, is a perennial herb with an ancient reputation for supporting the body’s healing processes. It earned the folk name “knitbone” because of its historical use in traditional medicine to externally treat fractures, sprains, and bruises. The plant’s leaves and roots have been applied topically for centuries over affected areas to promote the mending of damaged tissue. This article focuses on the preparation and safe external use of comfrey to support bone and tissue healing.
The Compounds Supporting Tissue Repair
The herb’s ability to aid tissue repair is attributed to a complex mixture of natural compounds. The most notable is allantoin, highly concentrated in comfrey roots and leaves. Allantoin acts as a cell proliferant, promoting the growth of new cells necessary for the repair of bone, cartilage, and skin tissue. This compound stimulates the activity of fibroblasts, cells that synthesize the collagen and extracellular matrix needed to form new granulation tissue during healing.
Other compounds within the plant work alongside allantoin to provide comprehensive tissue support. Comfrey contains rosmarinic acid, recognized for its anti-inflammatory properties. This helps to reduce the swelling, pain, and redness often associated with injuries, creating an environment conducive to healing.
Mucilage, a sticky, gelatinous substance, also contributes to the herb’s soothing effects. Mucilage offers a hydrating and cooling action when applied topically, which can alleviate discomfort at the site of an injury.
Creating External Comfrey Preparations
The most common way to apply comfrey is by creating a poultice or compress, which delivers the beneficial compounds directly to the affected area. To make a fresh poultice, gather clean comfrey leaves and stems, roughly chop them, and crush them into a paste using a food processor or mortar and pestle. A small amount of liquid, such as water or cider vinegar, can be added to achieve a spreadable consistency. This paste is then spread onto a clean cloth, applied directly over the intact skin of the injury, and left in place for approximately four to six hours.
Another effective method is creating an infused oil that can be turned into a lasting salve. For the oil, dried comfrey root or leaf is steeped in a carrier oil like olive or avocado oil. Fill a jar about two-thirds full with the dried herb and cover it completely with the oil. This mixture can infuse in a cool, dark place for four to six weeks, or it can be gently heated in a crock pot on low for several hours for a quicker infusion.
Once the oil is strained to remove all plant matter, it is ready to be transformed into a salve. To solidify the oil, combine one cup of the infused oil with about four tablespoons of beeswax in a double boiler. Heat the mixture gently until the beeswax is fully melted. It is then poured into clean tins or jars and allowed to cool and solidify. This salve can be rubbed into the skin multiple times a day over a period of weeks.
Mandatory Safety Precautions for Use
Comfrey contains compounds that necessitate strict safety guidelines for its use. The plant naturally produces pyrrolizidine alkaloids (PAs), which are potent hepatotoxins. Internal consumption of comfrey in any form is strongly discouraged because PAs can cause severe and irreversible liver damage, specifically sinusoidal obstruction syndrome. The risk of toxicity from oral use has led to regulatory restrictions and bans on internal comfrey products in many countries.
Topical application is the only recommended use. Preparations must never be applied to broken skin, open wounds, or deep cuts. Applying comfrey to damaged skin increases the risk of PAs being absorbed into the bloodstream and reaching the liver. Topical application on intact skin is considered safe because the skin acts as a protective barrier, which is compromised by injury.
Topical use should also be limited in duration to minimize any potential systemic absorption of PAs. It is recommended to limit the use of comfrey preparations to a maximum of four to six weeks per year. Since a diagnosed bone fracture requires professional medical intervention, comfrey should only be used as a complementary remedy under the supervision of a healthcare professional.