Cramp Bark
Viburnum opulus
欧洲荚蒾
Pinyin: Ōu Zhōu Jiá Mí
Plant Family
Adoxaceae
Part Used
Bark (from stems and branches)
Origin
Europe, North America, Northern Asia
Safety Level
Safe
Overview
Cramp bark is a large shrub known for its distinctive bark that has powerful antispasmodic properties. It gets its common name from its traditional use for relieving muscle cramps of all types, especially menstrual cramps. The bark contains compounds that relax smooth muscle, making it valuable for uterine, intestinal, and respiratory spasms.
Traditional Chinese Medicine Properties
Nature (四气)
cool
Flavors (五味)
bitter, astringent
Meridians (归经)
uterus, liver, muscles
Health Benefits
Traditional Uses
- Menstrual cramps and PMS (primary use)
- Muscle cramps and spasms
- Irritable bowel syndrome (IBS) and intestinal cramps
- Asthma and bronchial spasms
- High blood pressure
- Arthritic pain
- Miscarriage prevention (historical use)
- After-pains following childbirth
Active Constituents
The key compounds responsible for this herb's therapeutic effects:
Usage & Dosage
How to Use
Tea, tincture, decoction, extract, capsule. Best taken before cramps start for prevention.
Suggested Dosage
Tea/decoction: 1–2 tsp dried bark per cup, simmer 10–15 min, 2–3x/day; tincture: 2–4 mL 3x/day (can take more frequently during acute cramps); capsules: 500 mg 2–3x/day. For menstrual cramps: start taking 1–2 days before period begins for best results.
Quality & Storage
Harvest Season
Bark is harvested in early spring (March–April) before buds open, or in autumn after leaf fall. Bark from young branches (2–3 years old) is preferred. It is carefully peeled from branches and dried in the shade.
Quality Indicators
Dried bark: brownish-gray to brown, in quills or chips, with slightly bitter, astringent taste. Should have a strong, characteristic odor. The inner bark surface should be smooth and slightly wavy. Quality is determined by valerenic acid and coumarin content.
Storage
Dried bark: airtight container in cool dark place, 2–3 years. Protect from light and moisture. Tinctures have a longer shelf life (3–5 years).
Safety Information
Contraindications
Pregnancy (uterine relaxant - though historically used to prevent miscarriage, best to avoid during pregnancy without practitioner guidance)Breastfeeding (insufficient data)Low blood pressure (may lower further)Children (insufficient data)Kidney disease (hydroquinone derivatives - high doses may be toxic to kidneys)Surgery (stop 2 weeks before - blood pressure effects)
Possible Side Effects
- Generally well-tolerated at recommended doses
- Mild digestive upset (nausea, vomiting) in high doses
- Drowsiness and sedation (especially with high doses or combined with sedatives)
- Allergic reaction (rare)
- May lower blood pressure (dizziness if already low)
- Long-term high-dose use may affect kidney function (theoretical)
Drug Interactions
- Sedatives, sleeping pills, and CNS depressants (additive sedative effect)
- Alcohol (increased drowsiness)
- Blood pressure medications (may lower blood pressure further - monitor)
- Blood thinners (mild effect)
- Muscle relaxants (additive effect)
- Generally moderate interaction potential
Note: Always consult with a qualified healthcare practitioner before starting any herbal supplement, especially if you are pregnant, nursing, have medical conditions, or take medications.
References & Research
Information on this page is based on traditional herbal knowledge and modern scientific research. For a comprehensive list of references, please refer to our full citations page.
ℹ️ Disclaimer
This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. The FDA has not evaluated these statements. Always consult a qualified healthcare provider before using herbal supplements.
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