PubMed-compiled information sheet
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Compiled from 29 PubMed articles · model: gemma4:31b
Summary
White willow (Salix alba) bark is a traditional remedy used for thousands of years as an anti-inflammatory, antipyretic, and analgesic [PMID:25997859, PMID:35203473].
Background
White willow (Salix alba) is a plant whose bark has been used since ancient times, with therapeutic potential noted in Egypt as early as 1534 BC [PMID:35203473]. It served as the natural precursor to the development of aspirin [PMID:14592543, PMID:22117784].
Traditional uses
Traditionally used to treat fever, inflammatory conditions, rheumatism, and pain [PMID:30000964, PMID:11192932, PMID:34944032].
Active compounds
The bark contains salicylic acid and its derivative salicin [PMID:30000964, PMID:40702178]. Other phenolic compounds identified include salidroside, saligenin, tremulodin, salicoylsalicin, salicortin, and tremulacin [PMID:31906808].
Mechanism of action
Willow bark extracts inhibit the cyclooxygenase (COX) enzyme, preventing the formation of prostaglandins that cause inflammation, pain, and fever [PMID:14592543]. In vitro studies also indicate down-regulation of inflammatory mediators tumor necrosis factor-α and nuclear factor-kappa B [PMID:25997859]. Salicin may also inhibit angiogenesis by blocking ROS-ERK pathways [PMID:24535656] and activate the bitter taste receptor TAS2R16 [PMID:40261795, PMID:26096905].
Clinical evidence
Evidence AArthritis
Meta-analysis of RCTs showed significant differences in pain relief and improvement in physical status compared to placebo [PMID:37895439].
Evidence CChronic lower back pain and osteoarthritis
A small number of clinical studies support the use of willow bark extracts for these conditions [PMID:25997859].
Safety & adverse effects
Common adverse effects are gastrointestinal, with some reports of allergic reactions [PMID:3160435 la]. There is a risk of increased bleeding in vulnerable individuals [PMID:31604354]. In vitro studies on human cultured leukocytes noted a genotoxic response [PMID:31906808, PMID:34674609].
Pregnancy & lactation
Willow bark is best avoided during breastfeeding because salicylic acid is excreted into breastmilk, and this excretion increases as maternal dosage increases [PMID:30000964]. Salicylates also cross the placenta and are eliminated slowly in newborns [PMID:31604354].
Drug interactions
Concurrent use with other salicylate-containing medicines increases the risk of bleeding and other salicylate-related adverse effects [PMID:31604354].
Evidence summary
Evidence for pain relief in arthritis is supported by a meta-analysis of RCTs (Level A). Other clinical applications for back pain and osteoarthritis are supported by a limited number of studies (Level C), while much of the remaining data is based on historical use or in vitro/animal models.
PubMed sources
- 1.PMID: 14592543 (2003) — The mechanism of action of aspirin. · Thrombosis research
- 2.PMID: 25997859 (2015) — Efficacy and Safety of White Willow Bark (Salix alba) Extracts. · Phytotherapy research : PTR
- 3.PMID: 30000964 (2006) — The first 3500 years of aspirin history from its roots - A concise summary. · Vascular pharmacology
- 4.PMID: 40702178 (2025) — Three-step biosynthesis of salicylic acid from benzoyl-CoA in plants. · Nature
- 5.PMID: 34944032 (2021) — From NSAIDs to Glucocorticoids and Beyond. · Cells