What the evidence says. Graded moderate: good short-term RCTs and a Cochrane review show real relief of low-back-pain flares at 240 mg salicin, but the largest, best-controlled osteoarthritis trial was null and the pooled arthritis effect is small with very-low GRADE certainty. (Moderate evidence: Several controlled trials; effects real but modest or context-dependent.)
What is White Willow Bark?
White Willow Bark (Salix alba) is a joint and skin supplement used for ease low-back pain flares. NutriDex grades the human evidence as Moderate. White willow bark is the plant from which salicin — the precursor of aspirin's active ingredient — is derived. Its best evidence is for acute flares of chronic low-back pain: in a 210-patient RCT, 39% of people on 240 mg salicin/day were pain-free in the final week versus 6% on placebo, and a Cochrane review rated this 'moderate' evidence, with one trial showing rough parity to rofecoxib. For osteoarthritis the picture is mixed: a small 2-week trial found a modest WOMAC pain drop (14% vs placebo), but the larger, more rigorous 2004 trial (240 mg salicin vs diclofenac vs placebo) found no benefit over placebo while diclofenac clearly worked. A 2023 meta-analysis of arthritis trials found only a small pooled effect (SMD −0.31) rated very-low certainty. Useful and generally well tolerated, but milder and less consistent than standard analgesics.
Purported Benefits
✓Ease low-back pain flares
✓Relieve osteoarthritis pain
✓Anti-inflammatory support
✓Aspirin-like pain relief
Evidence by outcome
The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.
Outcome
Evidence
Effect
Studies
Ease acute low-back pain flares210-patient RCT showed 39% pain-free on 240 mg salicin vs 6% placebo; Cochrane rated moderate.
Moderate
↑ benefit · moderate
2
Relieve osteoarthritis painSmall trial positive but larger rigorous RCT found no benefit; meta-analysis SMD -0.31, very-low certainty.
Willow bark acts like a mild aspirin: it can cause stomach upset, GI bleeding and allergic reactions, and is dangerous in people with aspirin/salicylate allergy (anaphylaxis has been reported). It should not be given to children or teens with viral illness (Reye's syndrome risk) and is best avoided in pregnancy, peptic ulcer, asthma, and kidney or liver disease. It can add to the bleeding risk of warfarin and other anticoagulants/antiplatelets and may interact with other NSAIDs, methotrexate and some blood-pressure or diabetes medications — talk to a clinician before combining. Educational only — always check with your doctor or pharmacist before combining White Willow Bark with any medicine.
White Willow Bark drug interactions
Known or theoretical interactions between White Willow Bark and common medications — educational, not exhaustive. Always check with your doctor or pharmacist before combining White Willow Bark with any medicine.
White Willow Bark is most often taken for Ease low-back pain flares, Relieve osteoarthritis pain, Anti-inflammatory support, Aspirin-like pain relief. Aspirin's botanical ancestor, used for back and joint pain.
Does White Willow Bark work — what does the evidence say?
Moderate evidence. Several controlled trials; effects real but modest or context-dependent. White willow bark is the plant from which salicin — the precursor of aspirin's active ingredient — is derived. Its best evidence is for acute flares of chronic low-back pain: in a 210-patient RCT, 39% of people on 240 mg salicin/day were pain-free in the final week versus 6% on placebo, and a Cochrane review rated this 'moderate' evidence, with one trial showing rough parity to rofecoxib. For osteoarthritis the picture is mixed: a small 2-week trial found a modest WOMAC pain drop (14% vs placebo), but the larger, more rigorous 2004 trial (240 mg salicin vs diclofenac vs placebo) found no benefit over placebo while diclofenac clearly worked. A 2023 meta-analysis of arthritis trials found only a small pooled effect (SMD −0.31) rated very-low certainty. Useful and generally well tolerated, but milder and less consistent than standard analgesics.
What is the typical dose of White Willow Bark?
Standardized extract delivering 120–240 mg salicin/day; the 240 mg dose carries most of the positive trial evidence.
Is White Willow Bark safe? Any cautions or side effects?
Willow bark acts like a mild aspirin: it can cause stomach upset, GI bleeding and allergic reactions, and is dangerous in people with aspirin/salicylate allergy (anaphylaxis has been reported). It should not be given to children or teens with viral illness (Reye's syndrome risk) and is best avoided in pregnancy, peptic ulcer, asthma, and kidney or liver disease. It can add to the bleeding risk of warfarin and other anticoagulants/antiplatelets and may interact with other NSAIDs, methotrexate and some blood-pressure or diabetes medications — talk to a clinician before combining.
How many studies support White Willow Bark?
NutriDex cites 9 sources for White Willow Bark, graded "Moderate".
Does White Willow Bark interact with any medications?
Yes — known or theoretical interactions include: Antiplatelet drugs (aspirin, clopidogrel) (avoid), Blood thinners (warfarin, DOACs) (caution). This is educational and not exhaustive; always check with your doctor or pharmacist before combining White Willow Bark with any medicine.
Cite this page
APA
Peh, D. (2026). White Willow Bark (Salix alba): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 16 Sept 2026, from https://nutridex.info/s/white-willow
BibTeX
@misc{nutridex_white_willow,
author = {Peh, Daryl},
title = {White Willow Bark (Salix alba): Benefits, Dosage, Side Effects \& Evidence},
year = {2026},
howpublished = {NutriDex --- The Supplement Research Compendium},
url = {https://nutridex.info/s/white-willow},
note = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-09-16}
}
For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.