Efficacy and tolerance of a comfrey root extract (Extr. Rad. Symphyti) in the treatment of ankle distorsions: results of a multicenter, randomized, placebo-controlled, double-blind study

Effect of a blend of comfrey root extract (Symphytum officinale L.) and tannic acid creams in the treatment of osteoarthritis of the knee: randomized, placebo-controlled, double-blind, multiclinical trials

“…Botanicals such as stinging nettle, 39 devil's claw, turmeric, and ginger 40 have yielded positive results, whereas avocado soybean fraction, rose hip, and seed powder showed moderate positive results and Boswellia serrata gum resin registered poor outcomes. 41 Previous studies using comfrey have all suggested that the herb is effective in treating edema 15,22 and pain associated with OA. Previous studies have found a 46% 42,43 and a 54.7% 24 reduction in OA knee pain following a regimen of comfrey cream use compared with a 10.7% improvement in a placebo group.…”

“…Initial pain improvement and subsequent leveling off were also observed in 2 similar comfrey extract studies. 15,21 Indeed, the placebo effect in pain studies can be significant and has been labeled a nuisance. 44 For example, one study found a 49% placebo improvement in back pain, 45 whereas another found a 57% improvement in bone metastasis pain 46 , prompting some to suggest that a placebo is effective in treating symptoms of OA.…”

“…49 Studies using comfrey have reported reductions in joint pain after 7 days 24 and 12 days 42,43 and reductions in ankle pain and swelling in as little as 4 days. 15 Initial improvements (observation in the first 2 weeks) in the current study demonstrated pain improvement by 30.9% for the 10% cream, 31.3% for the 20% cream, and 19.6% for the placebo; stiffness improvement for the 10% and 20% comfrey cream and placebo by 19.6%, 46.8%, and 22.1%, respectively; and function improvement of 20.5% (10% cream), 45.5% (20% cream), and16.3% (placebo).…”

“…For instance, Bleakley et al 20 concluded that comfrey root cream decreases pain and improves function in acute ankle sprains. Similarly, another study 15 concluded that a cream of comfrey root extract, when administered on acute ankle sprains, was clearly superior (P b .0001) to a placebo in the reduction of pain of edema and in the increase in mobility. In addition, the authors found no adverse effect in the use of the comfrey cream.…”

“…In Germany, comfrey has been used in medicine since 1920 for the treatment of musculoskeletal conditions. 15 It has been suggested that the efficacy of comfrey is primarily due to its anti-inflammatory, analgesic, granulating promoting, and antiexudative properties. 16,17 Comfrey pharmacological components include rosmarinic acid and tannin.…”