What is cramp bark (Viburnum opulus) used for?

Cramp bark is traditionally used as an antispasmodic herb to relieve uterine cramps during menstruation, muscle spasms, and leg cramps. Its primary bioactive compound, scopoletin, is theorized to reduce smooth muscle contractions by blocking calcium ion influx. However, no human clinical trials have confirmed these effects, so its use remains based on historical and traditional practice.

What is the active compound in Viburnum opulus?

The main bioactive compounds in Viburnum opulus bark are scopoletin (a coumarin), viburnin (a bitter iridoid glycoside), isovaleric acid esters, and tannins. Scopoletin is most frequently cited as the primary antispasmodic agent, with preclinical evidence suggesting it inhibits smooth muscle contraction via calcium channel interference. Tannins may contribute astringent and mild anti-inflammatory effects.

Is Viburnum opulus safe during pregnancy?

Viburnum opulus is contraindicated during pregnancy due to its traditional use as a uterine relaxant and the theoretical risk of stimulating or altering uterine muscle tone. While it has historically been used to prevent miscarriage in some folk traditions, the absence of safety data from clinical trials makes its use in pregnancy inadvisable. Pregnant individuals should consult a healthcare provider before using any cramp bark preparation.

Does Viburnum opulus interact with any medications?

Viburnum opulus may interact with calcium channel blockers such as verapamil or amlodipine, since scopoletin is hypothesized to share a similar mechanism of inhibiting calcium ion influx in smooth muscle cells. Combining it with other antispasmodics, benzodiazepines, or centrally acting muscle relaxants like cyclobenzaprine could theoretically produce additive sedative or muscle-relaxing effects. No formal drug interaction studies have been conducted in humans, so caution is recommended with any concurrent medication use.

What is the typical dosage of Viburnum opulus?

Traditional dosing guidelines suggest 2–4 mL of a 1:5 liquid tincture taken up to three times daily, or a decoction prepared from 1–2 g of dried bark per cup of water. These dosage recommendations originate from historical European and North American herbal medicine traditions and have not been validated by controlled clinical trials. Standardized extract products are not widely available, making consistent dosing difficult to achieve.

What is the difference between Viburnum opulus and Viburnum prunifolium (black haw)?

Both Viburnum opulus (cramp bark) and Viburnum prunifolium (black haw) are traditional antispasmodics used for menstrual and muscle cramps, but they come from different species with distinct geographic origins—opulus is native to Europe and Asia, while prunifolium is native to North America. While their traditional uses overlap significantly, they contain different phytochemical profiles, with opulus being characterized by scopoletin and viburnin. Clinical evidence is limited for both species, so their relative efficacy remains unestablished.

What is the best form of Viburnum opulus supplement—dried bark, liquid extract, or standardized extract?

Traditional preparations typically use dried bark decoctions or tinctures, which have been used historically for centuries, though no clinical studies directly compare absorption rates between forms. Standardized extracts are marketed with defined marker compounds, but since no active compounds have been definitively confirmed clinically, standardization value is unclear. Liquid extracts may offer faster absorption compared to dried bark, but this advantage has not been clinically validated for Viburnum opulus specifically.

Who should avoid taking Viburnum opulus, and are there specific populations at risk?

Viburnum opulus should be avoided by pregnant and breastfeeding women due to its traditional use as an emmenagogue (menstruation promoter) and potential uterotonic effects, though clinical evidence of harm is lacking. Individuals taking anticoagulants or antiplatelet medications should consult a healthcare provider, as some Viburnum species may have mild anticoagulant properties. People with hormone-sensitive conditions should also exercise caution given its historical use in menstrual regulation.

Viburnum opulus

Viburnum opulus, commonly called cramp bark, contains the coumarin scopoletin and the bitter iridoid viburnin as its primary bioactive compounds. These constituents are believed to inhibit smooth muscle contractions by interfering with calcium ion mobilization, making it a traditional antispasmodic for uterine and skeletal muscle cramps.

Category: European Evidence: 2/10 Tier: Traditional

Viburnum opulus — Hermetica Encyclopedia

Origin & History

Viburnum opulus, commonly known as cramp bark or guelder rose, is a deciduous shrub native to Europe, northern Africa, and central Asia, belonging to the Caprifoliaceae family. The medicinal parts are the dried stem bark, harvested from wild or cultivated plants, typically extracted as liquid extracts, tinctures, decoctions, or powdered forms without specific standardized methods.

Historical & Cultural Context

Viburnum opulus has been used in Western herbal medicine traditions (European and North American) for over 200 years as an antispasmodic for cramping pains. Traditional applications focused on menstrual cramps, uterine spasms, and leg cramps, with secondary uses including anti-inflammatory and vascular tonic effects.

Health Benefits

• Traditional antispasmodic for menstrual cramps and uterine spasms (Traditional use only - no clinical trials available)
• May help with leg cramps and muscle spasms (Traditional use only - no clinical evidence)
• Potentially supports smooth muscle relaxation (Theoretical mechanism via scopoletin - unconfirmed clinically)
• Traditional use for promoting menstruation as an emmenagogue (Historical use only - no clinical data)
• May have hypotensive effects (Traditional attribution - no clinical studies found)

How It Works

Scopoletin, a coumarin derivative in Viburnum opulus, is hypothesized to act as a smooth muscle relaxant by inhibiting calcium influx through voltage-gated calcium channels, reducing the contractile response of uterine and vascular smooth muscle. Viburnin, a bitter principle, may also contribute to antispasmodic activity through unclear neurogenic pathways, possibly involving modulation of acetylcholine-mediated contractions. Additionally, tannins and isovaleric acid esters present in the bark may exert mild sedative effects on peripheral nerve endings, further reducing involuntary muscle spasm.

Scientific Research

No human clinical trials, RCTs, or meta-analyses specific to Viburnum opulus were identified in the available sources. Clinical evidence is completely lacking, with usage based entirely on traditional Western herbalism practices spanning over 200 years.

Clinical Summary

No randomized controlled clinical trials on Viburnum opulus have been published to date, leaving its efficacy entirely unsupported by modern clinical evidence. The available data consist exclusively of traditional ethnobotanical records, historical pharmacopoeia entries in European and North American herbalism, and a small number of preclinical in vitro studies demonstrating spasmolytic activity in isolated animal uterine tissue. One in vitro study demonstrated that scopoletin reduced oxytocin-induced contractions in rat uterine strips, but this cannot be extrapolated to human clinical outcomes. Given the complete absence of human trials, all purported benefits remain speculative, and Viburnum opulus is classified as a traditional-use-only ingredient.

Nutritional Profile

Viburnum opulus (Guelder Rose / European Cranberrybush) berries contain: **Organic acids**: citric acid (~1.2–2.0% fresh weight), malic acid, and traces of valeric acid and isovaleric acid. **Ascorbic acid (Vitamin C)**: approximately 35–80 mg per 100 g fresh fruit (varies significantly by cultivar and ripeness; some Russian cultivars report up to 138 mg/100 g). **Anthocyanins**: primarily cyanidin-3-glucoside and cyanidin-3-rutinoside, total anthocyanin content approximately 30–80 mg/100 g fresh weight. **Other phenolics**: chlorogenic acid (~15–45 mg/100 g), catechin, epicatechin, and proanthocyanidins (condensed tannins); total phenolic content reported at approximately 250–600 mg GAE/100 g fresh fruit. **Carotenoids**: β-carotene approximately 0.4–1.5 mg/100 g fresh fruit, with minor lutein and zeaxanthin. **Pectin (soluble fiber)**: approximately 0.6–1.2 g/100 g fresh fruit. **Sugars**: total sugars approximately 6–10 g/100 g (mainly glucose and fructose; low sucrose). **Minerals**: potassium (~150–200 mg/100 g), calcium (~30–40 mg/100 g), magnesium (~12–18 mg/100 g), phosphorus (~20–30 mg/100 g), iron (~0.4–0.6 mg/100 g). **Coumarins**: scopoletin and scopolin found primarily in bark (approximately 0.02–0.08% dry weight of bark), which are considered the principal bioactive compounds responsible for antispasmodic activity. **Iridoids**: traces of aucubin and other iridoid glycosides in bark and leaves. **Triterpenes**: oleanolic acid and ursolic acid in bark. **Fatty acids in seeds**: linoleic acid (~45–55%), oleic acid (~20–30%), palmitic acid (~8–12%). **Macronutrient approximate values per 100 g fresh fruit**: energy ~40–55 kcal, protein ~0.4–0.7 g, fat ~0.5–1.0 g, carbohydrates ~8–12 g, dietary fiber ~2–4 g. **Bioavailability notes**: Vitamin C is readily bioavailable but degrades rapidly during heat processing (losses of 30–60% upon cooking/juicing). Anthocyanins have relatively low oral bioavailability (~1–5%), though gut microbial metabolites (protocatechuic acid, phenylacetic acids) may contribute to systemic effects. Scopoletin bioavailability from bark preparations is poorly characterized in humans. The high organic acid content of the berries contributes a distinctly tart/bitter flavor, and the presence of viburnin (a bitter glycoside) in raw fruit may cause gastrointestinal upset if consumed in large quantities without processing.

Preparation & Dosage

No clinically studied dosage ranges are available due to absence of clinical trials. Traditional forms include powdered bark or liquid extracts (e.g., 1:5 tincture), but no standardized doses or specific concentrations have been established. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Valerian root, Passiflora incarnata, Magnesium, Black cohosh, Willow bark

Safety & Interactions

Viburnum opulus is generally considered low-risk at traditional doses but may cause nausea, stomach upset, or diarrhea in sensitive individuals due to its tannin and isovaleric acid content. Because of its theoretical uterine-relaxant activity, it is contraindicated during pregnancy and should be avoided by individuals at risk of preterm labor. It may potentiate the effects of calcium channel blocker medications such as amlodipine or verapamil, and caution is warranted when combined with antispasmodic drugs or centrally acting muscle relaxants. No established safe dosage has been validated in clinical trials; typical traditional preparations use 2–4 mL of a 1:5 tincture or 1–2 g of dried bark in decoction form.