Cochrane Summaries

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Topical herbal therapy for treating osteoarthritis

Cameron M, Chrubasik S
Published Online: 
5 June 2013

This summary of a Cochrane review presents what we know from research about the effects of herbal therapies applied to the skin in people with osteoarthritis.

The review shows that in people with osteoarthritis:

Arnica gel probably improves pain and function as well as non-steroidal anti-inflammatory drugs do;

Capsicum extract gel probably will not improve pain or function more than placebo;

Comfrey extract gel probably improves pain more than placebo;

Chinese herbal patches probably improve pain and function slightly more than placebo.

Herbal therapies may cause side effects; however we do not have precise information about side effects and complications. This is particularly true for rare but serious side effects. Possible side effects may include skin irritations.

What is osteoarthritis and what is herbal therapy?

Osteoarthritis (OA) is a disease of the joints (commonly knee, hip, hands). When joints lose cartilage, bone grows to try to repair the damage. Instead of making things better, however, the bone grows abnormally and makes things worse. For example, the bone can become misshapen and make the joint painful and limit movement. OA can affect your physical function, particularly your ability to use your joints.

Herbal medicines are defined as finished, labeled medicinal products that contain as active ingredients aerial or underground parts of plants, other plant material, or combinations thereof, whether in the crude state or as plant preparations (for example oils, tinctures).

Best estimate of what happens to patients with osteoarthritis who apply Arnica extract gel:

Arnica gel was compared to ibuprofen (a non-steroidal anti-inflammatory).

Pain (higher scores mean more severe pain): people who applied Arnica rated their pain to be 3.8 points lower (10.1 points lower to 2.5 points higher) than people who applied ibuprofen. After 3 weeks of treatment, people who applied Arnica rated their pain to be 40.4 and people who applied ibufrofen rated their pain to be 44.2 on a scale of 0 to 100.

Physical function (lower scores mean better function): people who applied Arnica rated their physical function to be 0.4 points lower (1.75 points lower to 0.95 points higher) than people who applied ibuprofen. After 3 weeks of treatment, people who applied Arnica rated their physical function to be 7.1 on a scale of 0 to 30, and people who applied ibufrofen rated their physical function to be 7.5.

Side effects: a greater proportion of people who applied Arnica reported side effects than did those who applied ibuprofen. Fourteen out of 105 people reported side effects with Arnica, and 8 out of 99 people reported side effects with ibuprofen.

Best estimate of what happens to patients with osteoarthritis who apply Capsicum extract gel

Capsicum extract gel was compared to placebo.

Pain (higher scores mean more severe pain): people who applied Capsicum rated their pain to be 1.0 point lower (6.76 points lower to 4.76 points higher) than people who applied placebo. After 4 weeks of treatment, people who applied Capsicum rated their pain to be 44.6, and people who applied placebo rated their pain to be 45.6 on a scale of 0 to 100.

Physical function (lower scores mean better function): people who applied Capsicum rated their physical function to be 2.64 points lower (9.51 points lower to 4.23 points higher) on a 0 to 96 point scale than people who applied placebo. After 4 weeks of treatment, people who applied Capsicum rated their physical function to be 32.15 on a scale of 0 to 96, and people who applied ibufrofen rated their physical function to be 34.79.

Side effects: more adverse events were reported among people who applied Capsicum than for those who applied placebo. Of the 338 adverse events reported, 272 occurred in people who applied Capsicum and 66 occured in people who applied placebo.

Best estimate of what happens to patients with osteoarthritis who apply comfrey extract cream

Comfrey extract cream was compared to placebo.

Pain (higher scores mean more severe pain): people who applied comfrey rated their pain to be 16.3 points lower (20.08 to 12.58 points lower) than people who applied placebo. After 3 weeks of treatment, people who applied comfrey rated their pain to be lower by 20.9 points from baseline, and people who applied placebo rated their pain to be lower by 4.6 points from baseline on a scale of 0 to 100.

Side effects: a smaller proportion of people who applied comfrey reported side effects than did those who applied placebo. Seven out of 110 people reported side effects with comfrey, and 15 out of 110 people reported side effects with placebo.

Chinese herbal medicine patches

Adhesive patches containing the Chinese herbal mixtures FNZG and SJG were compared to placebo. We are uncertain whether Chinese herbal patches affect osteoarthritis because this intervention was tested over seven days only.

Pain (higher scores mean worse or more severe pain): people who applied FNZG rated their pain to be 1.44 points lower (9.28 points lower to 6.40 points higher) and people who applied SJG rated their pain to be 1.08 points lower (6.28 points lower to 8.40 points higher) than people who applied placebo. People who applied FNZG rated their pain to be lower by 19.20 points from baseline, people who applied SJG rated their pain to be lower by 16.04 points from baseline, and people who applied placebo rated their pain to be lower by 17.68 points from baseline on a scale of 0 to 100.

Physical function (lower scores mean better function): people who applied FNZG rated their function to be 2.61 points lower (9.50 points lower to 4.28 points higher) and people who applied SJG rated their function to be 2.97 points lower (9.60 points lower to 3.66 points higher) than people who applied placebo. People who applied FNZG rated their physical function to be lower (better) by 5.04 points from baseline, people who applied SJG rated their physical function to be lower (better) by 6.71 points from baseline, and people who applied placebo rated their physical function to be lower (better) by 6.10 points from baseline on a scale of 0 to 96.

Side effects: a greater proportion of people who applied herbal patches reported side effects than did those who applied placebo patches. Five out of 60 people reported side effects with FNZG, 4 out of 60 people reported side effects with SJG, and 0 out of 30 people reported side effects with placebo.

Other topical products

We are uncertain whether other topical herbal products affect osteoarthritis pain and function because the evidence available from these studies was of low to very low quality. FNZG patches were compared head-to-head with SJG patches. Marhame-Mafasel compress was compared to placebo. Stinging nettle leaf was compared with two placebos in two different studies of people with osteoarthritis of the thumb or of the knee.