Can modern science turn an ancient healing herb with potentially dangerous toxicity into a safe salve? That was the goal of a German company that has created a new product from an herb—comfrey—used traditionally to heal wounds and ease pain. Taking comfrey as a tea or capsule can harm your liver, and in fact, the US Food and Drug Administration (FDA) has advised the herb industry to not use comfrey as an ingredient in supplements. But now the herb is on the market again and may make a big comeback here as a topical ointment for treating back pain, arthritis, sprains and wounds. If you have pain, it sounds wonderful…but is it safe, and should you try it?


You might wonder why a toxic herb has a long tradition as a healing remedy. Here’s why: It is “very effectual…for outward wounds and sores in the fleshy or sinewy part of the body,” wrote the great 17th-century British physician-herbalist Nicholas Culpepper in his Complete Herbal (originally published in 1653), adding that comfrey “give[s] ease to pained joints.” It’s been used internally for purposes as diverse as treating gout and aiding bone healing (hence the nickname knitbone) and, as recently as the 1970s and 1980s, it was all the rage in teas and capsules as well as in topical preparations.

That all changed in a flash when scientists discovered that comfrey can contain significant amounts of pyrrolizidine alkaloids (PAs), which can be very toxic to the liver. Sales dropped…comfrey disappeared from the shelves…the FDA issued a safety warning about oral comfrey products. Comfrey teas and capsules? Gone.

Topical comfrey preparations such as creams, ointments and salves remained on the market. The problem is that dangerous PAs can penetrate the skin, too, and build up in the bloodstream to levels that are dangerous to the liver. When used carefully—no more than 10 days at a time…no more than four to six weeks total in a year…never on open wounds (sorry, Culpepper!)…not in children or pregnant or nursing women…not in people with liver disease—topical comfrey may be used in relative safety.

However, relative safety may not be what you are looking for! That’s why there’s a new product that promises to make it really safe—PA-free comfrey. To learn more, we spoke with Mark Blumenthal, executive director of the nonprofit American Botanical Council in Austin, Texas.


According to Blumenthal, a few herbal product companies, all outside the US, now cultivate varieties of comfrey with very low levels of PA, and then they test the product to make sure it is PA-free.

He welcomes the new approach. “For many years, except for perhaps a few small manufacturers making small-production salves, there were virtually no external-use comfrey products on the market in the United States, so it’s good to see high-quality, safe, clinically tested and reliable products on the market,” he said.

In the US, only one PA-free comfrey product is currently available—Traumaplant Comfrey Cream. It’s manufactured in Germany and became available in the US in 2013. The cream is made from the flowers, stems and leaves of a special variety of comfrey that has been developed to be very low in PAs and then is run through a PA-removing extraction process—with the result that there are no detectable PAs in the product.

The new PA-free cream can be used not only for pain but also for cuts and abrasions, since there is no concern that PAs would get into the bloodstream. With PA-free comfrey, said Blumenthal, the beneficial compounds that promote tissue regeneration are able to work without danger of liver problems.


The research on the topical use of topical comfrey finds that it may have benefits for muscle, joint and flesh injuries. Topical comfrey may work by reducing inflammation and swelling. It contains at least two beneficial compounds, allantoin and rosmarinic acid (also found in rosemary), that can penetrate the skin and reduce pain and inflammation. Although much of the research has been supported by manufacturers with an interest in selling comfrey, it has been published in peer-reviewed journals, finding effectiveness for…

Sprains. A randomized study compared seven days of topical comfrey to seven days of topical diclofenac (a prescription nonsteroidal anti-inflammatory sold as Voltaren Gel). It was “observer blind,” meaning that the health professionals didn’t know which ointment each patient was getting. Results: Comfrey led to a bigger reduction in pain at rest (92%) than the prescription product (85%), pain during motion decreased 83% with comfrey and 72% with diclofenac, and swelling decreased 81% with comfrey and 69% with diclofenac.

Back pain. A randomized, double-blind study compared comfrey cream with a placebo cream for 120 participants with back pain. After five days, those who rubbed on the comfrey cream reported 95% reduction in pain intensity during movement, compared with just 38% reduction for placebo users.

Osteoarthritis. A randomized, double-blind study showed that after a three-week treatment with comfrey cream (three times daily), participants with osteoarthritis of the knee reported 55% less pain at rest and during movement. Participants using a placebo cream reported 11% improvement. Comfrey users also reported higher quality of life and more mobility.

Wound healing. A randomized, double-blind study compared the use of two comfrey creams, one with the same amount found in the Traumaplant preparation (10%), and the other with just 1%, in people with fresh abrasions. After two to three days, wounds were 49% smaller in participants treated with the full-strength comfrey, compared with 29% smaller in those treated with 1% cream.


So now that comfrey cream without PAs is available, will an oral formulation soon be on the market? “Probably not,” according to Blumenthal. “Comfrey has been shown to be effective in clinical trials for contusions, bruises, osteoarthritis, back pain and other indications that are best treated with topical comfrey extracts, not oral formulas. So there would be no benefit.” He added, emphatically, “It’s not recommended that people sip comfrey tea.”

But if you experience joint or muscle pain and you don’t want to reach for a pharmaceutical painkiller or anti-inflammatory medications (with their risks and side effects), this modern new version of an ancient healing salve with established safety is good news. For more nondrug ways to reduce pain, take a look at Bottom Line Health’s 4 Pain Fighters You’ve Probably Never Tried…But Should.