White Willow Bark: Uses, Benefits, Dosage & Safety

Last updated: June 2026 · Reviewed by the FactoWiki Editorial Team for clarity and source accuracy

What is White Willow Bark?

White willow bark (Salix alba and related species) is the bark of the willow tree, used since antiquity for pain and fever. Its key compound, salicin, is the natural forerunner of aspirin — aspirin was developed from salicylates first identified in willow and meadowsweet. Modern supplements are usually standardized to a set amount of salicin, commonly 240 mg per day.

What White Willow Bark is commonly used for

In supplements, White Willow Bark is used for pain and inflammation — especially low back pain and osteoarthritis — and sometimes for headaches. It is marketed as a gentle, plant-based alternative to anti-inflammatory drugs, which is both its appeal and the source of its cautions.

How White Willow Bark works

Salicin is converted in the body to salicylic acid, which reduces the production of prostaglandins — the same broad anti-inflammatory and pain-relieving mechanism as aspirin and other NSAIDs, though milder and slower. Willow bark's other compounds, including polyphenols and flavonoids, may add anti-inflammatory and antioxidant effects. Because it works like a mild aspirin, it carries aspirin-like benefits and risks.

What the evidence says

Here's an honest snapshot of what published research suggests about White Willow Bark — including where the evidence is limited.

• A randomised, double-blind trial in chronic low back pain (210 patients) found significantly more people taking willow bark standardized to 240 mg salicin became pain-free compared with placebo. (PubMed)
• By contrast, two randomised trials in osteoarthritis and rheumatoid arthritis found no significant benefit over placebo, in contrast to some earlier studies — so the arthritis evidence is mixed. (PubMed)
• General background is summarised by reputable health references; a 2023 meta-analysis reported overall pain relief in arthritis, underlining how mixed the picture is. (MedlinePlus)

Typical dosage used in studies

Extracts are usually standardized to around 120–240 mg of salicin per day, and the higher dose is what most positive trials used. Effects build over days to weeks. This is general information from research, not a recommendation.

Side effects and safety

Because it acts like aspirin, willow bark can cause stomach upset and carries similar risks. It should be avoided by people allergic to aspirin or salicylates and those with stomach ulcers, and — importantly — it should not be given to children or teenagers with a viral illness because of the risk of Reye's syndrome.

Medication interactions and who should avoid White Willow Bark

Sources & further reading

The evidence summary above is drawn from these sources. For general, authoritative background you can also consult:

• PubMed-indexed study (PMID 10936472)
• PubMed-indexed study (PMID 15517622)
• MedlinePlus
• NIH Office of Dietary Supplements
• NIH National Center for Complementary and Integrative Health

Frequently asked questions

Is white willow bark the same as aspirin?

It contains salicin, the natural compound aspirin was developed from, and works by a similar mechanism — but it is milder, slower-acting and not identical to aspirin.

Does willow bark work for back pain?

A good randomised trial found it helped chronic low back pain at 240 mg salicin per day, making this one of its better-supported uses.

Does willow bark help arthritis?

Results are mixed — some trials show modest benefit, but a well-known pair of trials found no significant effect over placebo.

Who should avoid willow bark?

People allergic to aspirin, those with ulcers or on blood thinners, pregnant women, and children or teens with a viral illness, because of Reye's syndrome risk.

How much salicin is used?

Positive trials generally used 240 mg of salicin per day. This is general information, not a dosing recommendation.