Evidence-based·Last reviewed May 30, 2026·How we grade evidence

White Willow

BotanicalWillow bark extractBest with a meal

Useful mainly for adults with chronic low back pain wanting a gentler, slower aspirin-like option.

Quick decision guide

May help most

adults with chronic low back pain wanting a gentler, slower aspirin-like option

Common dosing range

120–240 mg salicin/day (about 240–480 mg of 15% standardized extract)

When to expect effects

Days to weeks (chronic pain); 1–2 hours for acute, slower than aspirin

Watch out for

Shares aspirin's risks and interactions; avoid with aspirin/NSAID allergy and in children with viral illness

What is it

White willow (Salix alba) is a tree whose bark has been used since ancient times for pain, fever, and inflammation. The bark contains salicin, a compound that the body converts to salicylic acid, the active form of aspirin's precursor compound. White willow bark is sometimes called 'nature's aspirin'.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Worth considering if…

You have chronic low back pain and tolerate salicylates
You want a slower-onset, lower-peak alternative to aspirin
You accept building effects over days to weeks

Probably skip if…

You are allergic to aspirin or NSAIDs, or have ulcers/bleeding risk
It is for a child or teen with a viral infection (Reye's risk)
You are pregnant, on anticoagulants, or have kidney disease

Evidence at a glance

low back pain

Good Evidence
Effect
Moderate pain relief at higher salicin doses
Best fit
adults with chronic non-specific low back pain
Time
Days to weeks

osteoarthritis pain

Mixed Evidence
Effect
Small / inconsistent
Best fit
adults with osteoarthritis seeking an adjunct analgesic
Time
Days to weeks

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

low back pain

Supplement benefit
Good Evidence

RCTs of standardized willow bark providing 120–240 mg salicin/day show meaningful reductions in chronic low back pain versus placebo, with the higher salicin dose more effective. Salicin is converted to salicylic acid, which inhibits COX enzymes. This is the best-developed evidence base for white willow.

Effect size
Moderate pain relief at higher salicin doses
Time to effect
Days to weeks
Best fit
adults with chronic non-specific low back pain
Less likely
people needing rapid acute pain relief

Bottom line: Standardized willow bark, especially at 240 mg salicin/day, can meaningfully relieve chronic low back pain.

SourceChrubasik et al., 2000 — PubMed

osteoarthritis pain

Supplement benefit
Mixed Evidence

Trials of willow bark for osteoarthritis are mixed: some show modest pain relief while others find little benefit over placebo. Effects, where present, are smaller and less consistent than for low back pain. The salicylate mechanism is the same.

Effect size
Small / inconsistent
Time to effect
Days to weeks
Best fit
adults with osteoarthritis seeking an adjunct analgesic

Bottom line: Willow bark may modestly ease osteoarthritis pain, but the evidence is mixed and weaker than for back pain.

Evidence is mixed

Some osteoarthritis trials report relief while others show no significant advantage over placebo.

SourceBiegert et al., 2004 — PubMed· conflicting
SourceBiegert et al., 2004 — PubMed

How it works

White willow bark's primary active compound is salicin, a glycoside that is absorbed in the small intestine and then progressively converted into salicylic acid, the same active form created when the body metabolizes aspirin. Salicylic acid inhibits cyclooxygenase (COX) enzymes, reducing production of prostaglandins that mediate pain, inflammation, and fever. However, the conversion of salicin to salicylic acid is slower and produces lower peak blood levels than aspirin, which is rapidly hydrolyzed in the bloodstream. The slower onset and lower peak levels may explain why white willow bark generally causes less gastric irritation than aspirin, but it also means slower and milder analgesic effects. White willow bark also contains other compounds including polyphenols and flavonoids that may contribute to additional anti-inflammatory and antioxidant effects. The combination may produce broader effects than isolated salicin, though the relative contribution of these compounds is not fully characterized. Clinical evidence is most developed for low back pain and osteoarthritis.

How to take it

1. Typical dose
120–240 mg salicin/day
2. Timing
Divided once or twice daily; effects build over days to weeks for chronic pain
3. With food
With food to reduce GI effects
4. Split dosing
Twice-daily dosing is common depending on the product
5. How long to try
Trial 1–4 weeks for chronic pain conditions

What to track

Pain intensity and function
GI tolerance
Any ringing in the ears (high-dose salicylate sign)

4 commercial forms

Compare the main delivery options and what they’re best suited for.

Standardized bark extract

Most reliable form. Allows consistent salicin dosing.

Standardized to salicin content (typically 15%)

Dried bark powder

Traditional whole-bark form. Quality varies.

Variable salicin content

Liquid extract / tincture

Used in traditional herbalist preparations.

Alcohol or water-based extraction

Tea (decoction)

Traditional preparation. Less concentrated than capsule extracts.

Aqueous extraction; lower salicin extraction

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

GI upset (less common than aspirin)NauseaSkin rash

Serious risks

  • Allergic reactions in aspirin/NSAID-sensitive people

  • Aspirin-overdose-like effects (tinnitus, hyperventilation) at high doses

Who should avoid it

  • Children and adolescents with viral infections (Reye's syndrome risk)
  • People with aspirin/NSAID allergy, peptic ulcer, kidney disease, or bleeding disorders
  • Pregnant (especially third trimester) and breastfeeding women
  • People within 1–2 weeks of surgery

Pregnancy & breastfeeding

Avoid, especially in the third trimester.

Interactions

Anticoagulants (warfarin, heparin, dabigatran) / antiplatelets / NSAIDsMajor

Shares aspirin's effects; increases bleeding risk

MethotrexateMajor

May increase methotrexate toxicity

Beta-blockers and ACE inhibitorsModerate

May reduce their blood-pressure-lowering effect

Diabetes medicationsModerate

May enhance glucose-lowering effect

Choosing a product

What to look for on the label — and what to be skeptical of.

Look for…

Standardized salicin content (target 120–240 mg/day)
Stated species Salix alba
Clear per-dose salicin amount

Be skeptical of…

'Safe for everyone, unlike aspirin'
'No side effects'
'Works instantly'

Frequently asked questions

Is white willow bark just natural aspirin?⌄

White willow bark contains salicin, which the body converts to salicylic acid, the same active form created from aspirin metabolism. Effects are similar but slower and milder than aspirin, and white willow bark generally causes less gastric irritation.

Can I take white willow bark if I'm allergic to aspirin?⌄

No. Aspirin allergy or NSAID allergy is a contraindication to white willow bark. It shares aspirin's active metabolite and can trigger similar allergic reactions.

Should I give white willow bark to children?⌄

No. Like aspirin, white willow bark should not be given to children or adolescents with viral infections due to theoretical Reye's syndrome risk.

How long until white willow bark works for back pain?⌄

For chronic pain, effects typically emerge over days to weeks. Acute analgesic effects are slower in onset than aspirin or other NSAIDs.

Can I take white willow bark with blood thinners?⌄

Use with great caution and only under medical supervision. White willow bark may potentiate the effects of anticoagulants and antiplatelet drugs, increasing bleeding risk.

References by claim

low back pain

Chrubasik et al., 2000 — PubMed (2000) link

osteoarthritis pain

Biegert et al., 2004 — PubMed (2004) link

Track White Willow with Pilora

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Evidence-based·Last reviewed May 30, 2026·Evidence current as of May 30, 2026·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.