Cramp Bark

Botanical

What is it

Cramp bark (Viburnum opulus) is the dried bark of a deciduous shrub native to Europe and North America, traditionally used in herbal medicine to relieve muscle and menstrual cramps.

Evidence for 2 uses

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

Menstrual cramps (dysmenorrhea)

Mixed Evidence

Traditional use suggests it may ease menstrual cramping, but rigorous randomized trials are essentially absent. Evidence is ethnobotanical and based on smooth-muscle studies.

Muscle spasm

Mixed Evidence

Used historically as a general antispasmodic; modern clinical evidence in humans is lacking.

How it works

Cramp bark contains scopoletin, viburnin, and several other coumarins and iridoid glycosides that are thought to act as mild smooth-muscle relaxants. Traditional herbal practice positions it as an antispasmodic for uterine and skeletal muscle, often combined with other antispasmodic herbs. Mechanistic data in humans is limited; most evidence comes from in vitro and animal smooth-muscle studies rather than controlled clinical trials.

Dosage

No RDA, AI, or UL. Common traditional doses are 1-3 g of dried bark as a decoction, or 2-4 mL of tincture (1:5) up to three times daily. DSLD does not report a median dose across labels.

When and how to take it

No timing baseline established. Often taken at onset of cramping symptoms; no specific food-status requirement.

2 commercial forms

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

Dried bark (decoction)

Simmered as a tea, often combined with ginger or other digestive herbs.

Hot water extraction draws out water-soluble glycosides.

Tincture

Liquid extract used for flexible dosing; common 1:5 ratio.

Alcohol captures lipid-soluble constituents.

Safety

Generally considered safe in short-term traditional use. The plant contains small amounts of hydroquinone derivatives; very high doses or prolonged use have not been well studied. Berries are reportedly toxic when raw; bark preparations have a long history of human use without documented serious harm.

Who should be cautious

Pregnancy: avoid unless under qualified herbalist guidance, as it has been used to influence uterine tone. Caution with anticoagulant medications such as warfarin due to theoretical additive effects.

Interactions

No significant interactions reported in published clinical literature. Theoretical interaction with anticoagulants due to coumarin content, but clinical relevance is unclear.

Frequently asked questions

Does cramp bark actually work for period pain?⌄

Traditional herbalists report benefit, but high-quality clinical trials are lacking. Effects, if any, are likely modest.

Can I take cramp bark during pregnancy?⌄

Avoid in pregnancy unless directed by a qualified clinician; it has historically been used to influence uterine tone.

References

Cramp Bark on Wikidata — Wikidata link

Cramp Bark on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Cramp Bark (PubMed search) — PubMed link

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Evidence-based·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.