GradedHealth

Does willow bark help back pain and arthritis?

Willow bark extract eased low back pain in several trials. For arthritis, the trials disagree, so the evidence is limited.

Published October 2026

Short answer

Willow bark extract eased low back pain more than placebo in several small, short trials. For arthritis the results conflict, so the evidence is limited. Evidence grade C (Limited). Cochrane review of placebo-controlled trials plus one more placebo-controlled trial; small total sample and poor reporting, so downgraded; arthritis trials conflict.

Key takeaways

  • In a 4-week trial of 210 people with low back pain flare-ups, 39% of those on the higher dose were pain-free in the final week, against 6% on placebo [1].
  • A Cochrane review found white willow bark probably eases low back pain more than placebo in the short term, though its evidence is only moderate quality [2].
  • For osteoarthritis, one small trial found a modest pain benefit [3], while a larger trial found no significant difference from placebo [4].
  • A 2023 meta-analysis of arthritis trials found pain relief, but its authors say the evidence is still too uncertain [5].

The short version

Willow bark extract eased low back pain more than placebo in several small trials [2][1]. For arthritis, the results conflict, and the trials were small and short [3][4].

What the studies show

For low back pain, a Cochrane review found that white willow bark, at 120 or 240 mg of salicin a day, probably reduces pain more than placebo in the short term [2]. In a 4-week trial of 210 people with flare-ups of chronic low back pain, 39% of those taking the higher dose were pain-free for at least five days in the final week, against 6% on placebo [1]. In an open trial of 228 people, the extract gave about the same pain relief as the prescription anti-inflammatory rofecoxib, and it cost less [6].

For osteoarthritis, the trials disagree. In a 2-week trial of 78 people, pain scores fell 14% on willow bark and rose 2% on placebo [3]. A later trial of 127 people with osteoarthritis found no significant difference from placebo, although diclofenac did better [4]. A 2023 meta-analysis of five studies in 329 people with arthritis found pain relief compared with placebo, but its authors say the certainty of the evidence is still inadequate [5].

The nuances

Most trials tested a standardised extract that gave 120 to 240 mg of salicin a day, not tea or bark powder [7][8]. Most lasted 2 to 6 weeks [1][3][4], so long-term effects are not known.

A 24-week observational study of 436 people with mostly osteoarthritis or back pain found pain scores fell over the course of the study, but without a control group it cannot show that the extract caused the fall [9].

Some products combine willow bark with other ingredients. In a 100-person trial of Instaflex, a joint supplement that also contains glucosamine and other herbs, joint pain fell more than with placebo, but the result cannot be credited to willow bark alone [10]. The Cochrane review noted that trial reporting was generally poor [2].

What this means for you

The evidence supports a modest pain benefit for low back pain flare-ups [2][1]. It does not give a clear answer for arthritis yet [4][5]. Anyone thinking about willow bark for pain should talk to a doctor first, especially if they take blood thinners, pain medicines or have an aspirin allergy [7][11].

Willow bark contains salicin, which the body turns into salicylic acid, a compound related to aspirin [7]. Its most common side effects are stomach-related, and a few allergic reactions were reported [7]. One patient in the back-pain trial had a severe allergic reaction, perhaps to the extract [1].

Go deeper

  • Willow Bark — Willow bark extract eased low back pain more than placebo in several small trials, with the most consistent results for short-term flare-ups.

References

  1. Treatment of low back pain exacerbations with willow bark extract: a randomized double-blind study.. Am J Med, 2000.
  2. Herbal medicine for low-back pain.. Cochrane Database Syst Rev, 2014.
  3. Efficacy and tolerability of a standardized willow bark extract in patients with osteoarthritis: randomized placebo-controlled, double blind clinical trial.. Phytother Res, 2001.
  4. Efficacy and safety of willow bark extract in the treatment of osteoarthritis and rheumatoid arthritis: results of 2 randomized double-blind controlled trials.. J Rheumatol, 2004.
  5. Willow Bark (Salix spp.) Used for Pain Relief in Arthritis: A Meta-Analysis of Randomized Controlled Trials.. Life (Basel), 2023.
  6. Treatment of low back pain with a herbal or synthetic anti-rheumatic: a randomized controlled study. Willow bark extract for low back pain.. Rheumatology (Oxford), 2001.
  7. United States Pharmacopeia Safety Review of Willow Bark.. Planta Med, 2019.
  8. A systematic review on the effectiveness of willow bark for musculoskeletal pain.. Phytother Res, 2009.
  9. Willow bark extract STW 33-I in the long-term treatment of outpatients with rheumatic pain mainly osteoarthritis or back pain.. Phytomedicine, 2013.
  10. A commercialized dietary supplement alleviates joint pain in community adults: a double-blind, placebo-controlled community trial.. Nutr J, 2013.
  11. Potential interactions between alternative therapies and warfarin.. Am J Health Syst Pharm, 2000.