Willow Bark (Salix spp.) Used for Pain Relief in Arthritis: A Meta-Analysis of Randomized Controlled Trials

This study intends to assess the analgesic effects, physical facilitation, and safety of willow bark use in patients with arthritis. Our study was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. PubMed, Scopus, EMBASE, Web of Science, Cochrane, and ClinicalTrials.gov were searched for relative randomized controlled trials (RCTs) describing the efficacy or adverse events of willow bark in patients with arthritis until 12 April 2023. We used Cochrane ROB 2.0 and the Grading of Recommendations, Assessment, Development, and Evaluations system to evaluate the quality of studies and evidence. The meta-analysis was carried out by the fix-effects model. This study included five studies with six RCTs consisting of 329 patients with arthritis. The results showed significant differences in pain relief and improvement in physical status for patients with arthritis between willow bark treatment and placebo groups, and no significant differences in the risk of all adverse events in patients with arthritis between willow bark treatment and placebo. Owing to the potential bias, the certainty and evidence of our findings are still inadequate. Therefore, further RCTs are needed to confirm our results.