Comfrey, while considered an important herbal medicine, is controversial due to certain toxic components in it, which led to the U.S. Food and Drug Administration (FDA) to restrict the use of oral comfrey in dietary supplements.1
The dilemma is how to weigh the virtues of comfrey oil while considering the safety concerns that surround it. It has exhibited the potential to treat skin concerns and pain when used topically. Learn about comfrey oil, its practical applications and potential contribution to skin healing and maintenance, as well as the FDA's concerns about it.
What Is Comfrey Oil?
Comfrey oil is extracted from comfrey (Symphytum officinale), a perennial herb of the Boraginaceae family with a black, turnip-like root and large, hairy broad leaves bearings small, bell-shaped flowers. The plant is native to Europe and grows in damp, grassy places such as ditches and riverbanks. It is typically found in Ireland and Britain on ditches and riverbanks, but it also grows in profusion in North America and western Asia.
The plant has found widespread use in folk and herbal medicine for its properties as a healing agent. Its oil, for instance, is ideal as a base for salves and has been used in folk medicine to treat wounds and skin infections.
Uses of Comfrey Oil
Many of the beneficial properties of comfrey are attributed to its high content of allantoin, a substance that, according to the University of Maryland Medical Center, helps promote new skin cell growth, along with other substances that may work in reducing inflammation and maintaining healthy skin.2 Comfrey ointments have been used to help heal bruises and pulled muscles and ligaments.
Previously, comfrey was used in its tea form to aid in treating stomach problems, as well as ulcers, heavy menstrual periods, diarrhea, bloody urine, persistent cough and even cancer and chest pain.3 But experts have raised the alarm on consuming it, as it contains toxic substances called pyrrolizidine alkaloids (PAs), which damage the liver and can lead to fatality. According to the FDA, there is even evidence that PAs may be carcinogenic in sensitive body tissues when used orally.
The FDA reported this in 2001, when it sent letters to supplement manufacturers warning them not to put this herb in dietary supplements. Today, in the United States, comfrey is sold only in creams and ointments; countries like the United Kingdom, Australia, Canada and Germany have also banned the sale of comfrey-containing oral products.
But this isn't to ignore the potential healing effects of a common comfrey product, which is its oil. Comfrey oil can help you naturally address wound healing and skin issues4 such as scratches, rash (including diaper rash), bug bites (particularly spiders) and shallow wounds. It is also deemed helpful as a massage salve easing pain from arthritis, muscle aches, low back pain and soreness.5
Composition of Comfrey Oil
The comfrey plant contains substances thought to aid skin regrowth, primarily allantoin but also including rosmarinic acid and tannins. As already noted, it also contains pyrrolizidine alkaloids (PAs), which can be toxic to your liver.
Benefits of Comfrey Oil
Here are different comfrey oil benefits classified according to skin or health condition:6
• For skin rashes —– Comfrey oil can help in treating rashes. However, caution should be taken when it comes to deep wounds – the oil can help heal the skin so quickly that the new tissue may cover the wound before deep healing inside, resulting in an abscess or skin infection. Remember, too, that there are warnings against using comfrey on broken skin because its PAs can still be absorbed by your skin.
• As a poultice — A poultice is a good alternative if you have an infection but don't want to apply comfrey oil directly. Here's how to do it: Blend 4 cups of chopped comfrey leaves and stems with 1/4 cup of carrier oil, such as jojoba, almond or olive oil. Without straining out the herb, wrap the comfrey oil paste with a cotton cloth. Freeze this poultice before applying to help reduce pain and inflammation. Otherwise, you may apply it directly on the affected area for at least 30 minutes.
• For bone fractures — Apart from helping treat superficial wounds, comfrey oil has also been used for fractured bones or torn ligaments in areas of the body where it is not possible to place a cast, such as a rib. It can be applied directly onto your skin or in a poultice, potentially promoting faster healing. It is also said to help reconstruct torn muscles that might have been injured.
How to Make Your Own Comfrey Oil Infusion
Create an herbal oil infusion7 by infusing 2 cups of cut comfrey leaves in 4 cups of olive oil with a steady low heat (110 degrees) for two to three weeks. Strain and pour into a clean, dry bottle. Here is another comfrey oil infusion recipe, from Wildly Natural Skin Care.8
• 8 ounces comfrey leaf (70 percent)
• 4 ounces comfrey root (30 percent)
• Extra virgin olive oil, to cover, approximately 16 ounces
The roots should already be broken down by chopping. Break up the leaves by hand. To make this using the cold infusion method, put all the herbs in a 16-ounce glass jar, cover with olive oil and cap and shake. This can steep for 28 days. To strain, use a clean old shirt lined in a strainer, pour the mix through into a bowl and squeeze the shirt with herbs in it. The strained liquid is your comfrey oil.
• If possible, use freshly dried herbs for this purpose.
• To get fresh, dry comfrey root: Dig the root when it is dry weather. Clean by hand or use some water and a vegetable brush. Brush the root gently. Chop finely; lay out on a paper bag overnight.
• To get freshly dry leaves: Harvest, wipe the dirt off with a towel and allow to dry whole overnight.
How Does Comfrey Oil Work?
As an old European folk remedy, comfrey has many traditional and current uses, mostly focused on skin care. It is important to attribute many of these positive impacts to its high amounts of allantoin, a mucilaginous healing substance that causes cell growth.
Being mucilaginous, comfrey is commonly used for helping heal wounds, preventing scars and treating existing ones, along with decreasing dryness and flaking of skin. The oil appears to work as an anti-inflammatory, an analgesic and an aid in the healing of sprains and broken bones. It also demonstrates effectiveness in assisting treatment of atopic dermatitis, psoriasis and eczema.
All these potential benefits are obtained through topical application and not ingestion, largely due to the PAs or toxic, liver-destroying substances present in the plant.
Is Comfrey Oil Safe?
Comfrey oil appears to be safe when applied to unbroken skin in small amounts. Note that the poisonous chemicals present in comfrey can still pass through the skin, so they can still be absorbed if your skin is broken or if large amounts are administered. It is considered unsafe to take comfrey oil by mouth because of its PAs, which can cause liver damage, lung damage and cancer. The FDA has recommended that supplement manufacturers not sell any oral form of comfrey.
While a Garden Web community forum9 argues that the pyrrolizidine alkaloids (PAs) in comfrey are less toxic than those found in known poisonous plants, such as ragwort, and questions whether PAs cause cancer outside of laboratory experiments, I advise that you err on the side of caution: Stick to prudent topical use of comfrey oil and avoid ingesting any comfrey-based product. Pregnant and breastfeeding women, along with the elderly and children, are also better off avoiding the use of this oil.
Side Effects of Comfrey Oil
There are no known scientific reports of interaction between comfrey and conventional drugs.10 But some herbs that have also been known to cause liver problems — such as kava, skullcap and valerian — should not be used while using comfrey products because of the increased risk for liver damage.