People have cultivated and used comfrey as a medicinal herb for centuries. There are about 40 species that are native to Europe and parts of Asia. For the health benefits of comfrey, the plants were also brought to Northern America. 

Comfrey leaves and root cuttings have been used as herbal medicines for over 2000 years. Back then, they were applied as salves or poultices to heal wounds and bone fractures. The herb was also used for inflammations and muscle or joint complaints. Other traditional comfrey uses also included internal use in the form of tea.

For efficacy and safety reasons, nowadays the recommendation is to use comfrey only on the skin. The treatment of blunt injuries such as strains or sprains and muscle pain is well supported by clinical studies.

As it is easy to grow comfrey, the flowering plants can be found in many gardens today. However, some species can quickly spread because of their huge root systems.

Symphytum asperum is called rough or prickly comfrey. Coarse hairs cover their stems and leaves. This species is the tallest and mostly grown as an ornamental.

Symphytum grandiflorum, better known as large-flowered or creeping comfrey, has creamy flowers and is often used in gardening.  

Symphytum x uplandicum and S. officinale are both widely used in herbal medicines. Their roots and leaves contain two important active compounds called allantoin and rosmarinic acid. 

However, they also contain certain alkaloids that can harm the liver. Therefore, some Symphytum x uplandicum varieties have been cultivated that are alkaloid-free. They are known as “Bocking no. 4”,  “Bocking no. 14” and “Harras”.

Comfrey plants are hardy perennials. Like most members of the borage family, their leaves and stems are hairy.

S. uplandicum can grow up to around 120 cm or 4 feet tall. Its bristly stems carry large oblong leaves.

The nodding flowers are bell-shaped. They are pink when they open but turn to blue or purple when they mature. They appear in clusters and bloom from May to August.

The plants have deep roots that help them spread easily. In the wild, comfrey occurs in moist grasslands and riverbanks. In gardens, they grow best in partial to full sun.

The name comfrey is thought to derive from Latin ‘confera’, meaning to knit together. The French name consoude comes from souder, meaning to weld or knit together.

The scientific name Symphytum is believed to come from the Greek words symphyo and phyton. Symphyo means to join, and phyton means plant.

They all refer to the traditional plant used to heal wounds and fractures, as does the old name knit bone or boneset.

Comfrey as a medicinal plant

Comfrey has a long-standing history as a medicinal herb to help with inflammation, pain, and wound healing.

Modern research confirms that topical use of comfrey benefits particularly acute blunt trauma. Both plant extracts from the leaves or the roots have strong clinical records.

Four double-blind RCT clinical trials tested the efficacy of a 10% comfrey extract for different complaints. This extract was made from the aerial parts of a PA-free Symphytum x uplandicum cultivar (Traumaplant cream).

The conditions tested were muscle pain as well as accidental and sports injuries (acute ankle sprain/distortion). These studies showed that the comfrey cream significantly reduced muscle, back, and ligament pain caused by sprains or strains.

Further, wound healing in adult patients and wound healing in children was studied. The studies reported faster healing of abrasions and minor wounds. The product was well tolerated on intact and broken skin. 

However, not all comfrey products are suitable for use on open skin. Always verify the usage in the package leaflet before using a product.     

In the past, people were taking comfrey root and leaf extracts also by mouth. Yet, the plant naturally contains compounds called pyrrolizidine alkaloids or PAs. PAs are harmful when ingested as they can cause liver problems and increase the risk of liver damage. 

Therefore, the Food and Drug Administration (FDA) and Health Canada have restricted the use of comfrey in creams or ointments. Also, products in Canada must be tested to be PA-free.

Benefits of topical usage include:

• anti-inflammatory (helps with inflammations)

• analgesic (relieves pain)

• tissue regenerating (helps with wound healing) effects

Current uses of comfrey extract include the treatment of back pain, blunt injuries, bruises, strains, and sprains. Most comfrey products are available as creams or ointments.

However, comfrey leaves or roots are still sold dried or as tea. It is important to keep in mind that Health Canada recommends only using topical products. They also require testing comfrey products to ensure the absence of PAs.

What makes Symphytum x uplandicum different?

When used on the skin, Symphytum helps to relieve pain and inflammation.  

Because of concerns about toxic PAs, alkaloid-free cultivars of S. x uplandicum have been cultivated. The absence of PAs in this particular Symphytum cultivar even allows its use on abrasions and minor wounds.

Cautions and drug interactions

You should not ingest comfrey because of the risk that it may cause liver disease over time.

PA-free Symphytum is generally well tolerated when applied to the skin. However, some people with hypersensitivities may experience skin reactions as side effects. These include redness or irritation of the skin, itching, rash, and eczema. In this case, discontinue use.

Comfrey products should only be used during pregnancy or while breastfeeding after having consulted a healthcare practitioner. 

You should also talk to your doctor if the treated condition persists or worsens. 

Pascoe products that contain Comfrey: