Limited evidenceWomen's health

Cramp Bark

A traditional antispasmodic bark with real smooth-muscle activity in the laboratory but essentially no controlled human data for menstrual cramps. The reputation rests on 19th-century practice, not on trials.

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What the science says

Menstrual cramps Limited evidence
No modern randomized trial has tested Viburnum opulus for dysmenorrhea. A phytochemistry and pharmacology review documents antispasmodic and anti-inflammatory activity in cell and animal models only.
Smooth muscle relaxation Limited evidence
The one modern human trial of a Viburnum opulus (gilaburu) extract tested it against tamsulosin for passing distal ureteral stones and reported comparable expulsion rates. That is indirect support for a smooth-muscle effect, not evidence for menstrual pain.

Dosage & safety

Studied doseNo trial-established dose for cramps. Traditional use is 2-4 g of dried bark as a decoction, or 4-8 ml of tincture, taken two to three times daily during pain.

SafetyContains salicylates, so avoid with aspirin sensitivity and use caution with anticoagulants. Not established as safe in pregnancy or breastfeeding. Kidney irritation has been raised as a theoretical concern with prolonged use.

How to take it

TimingAt the first sign of cramping, repeated every few hours through the painful days.

With food?With food if the decoction upsets your stomach.

Worth knowingPeriod pain that is new, worsening or unresponsive deserves a check for endometriosis or fibroids rather than a stronger tincture.

Interactions

With medications

warfarin, DOACs and antiplatelet drugs
Cramp bark contains salicylates, which may add to bleeding risk. do not combine without medical supervision

With other supplements

fish oil, ginkgo and high-dose garlic
Additive effects on platelet function. avoid stacking, especially before surgery

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does cramp bark work for period pain?

No modern randomized trial has tested cramp bark (Viburnum opulus) for menstrual cramps, so the evidence is limited. Its antispasmodic activity is shown only in cell and animal models.

Does cramp bark relax muscles?

The one modern human trial of a Viburnum opulus extract found it comparable to tamsulosin for passing ureteral stones, indirect support for a smooth-muscle effect. That is not evidence that cramp bark eases menstrual pain.

How much cramp bark should I take?

Cramp bark has no trial-established dose; traditional use is 2-4 g of dried bark as a decoction or 4-8 ml of tincture, two to three times daily during pain.

Is cramp bark safe with blood thinners?

Cramp bark contains salicylates, which may add to bleeding risk with warfarin, DOACs and antiplatelet drugs, so do not combine without medical supervision. Avoid it if you are aspirin-sensitive, and its safety in pregnancy is not established.

Scientific references

Viburnum opulus L.-A Review of Phytochemistry and Biological Effects
Kajszczak D, Zakłos-Szyda M, Podsędek A — Nutrients, 2020
Gilaburu extract (Viburnum opulus Linnaeus) is as effective as Tamsulosin in medical expulsive therapy of distal ureteral calculi
Gok B, Tarik Atik Y, Uysal B, Koc E, Tastemur S, İbrahim Cimen H — Int J Clin Pract, 2021

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