Cramp bark
Cramp bark suppliers and sourcing guide
Cramp bark is the dried stem and branch bark of Viburnum opulus, a deciduous shrub of Europe, northern Asia and North America also known as guelder rose. The bark is stripped, dried and sold cut or powdered, or extracted with water and ethanol into liquid tinctures and dry extracts. It is traded as a traditional herb and is rarely standardized to a marker compound, so identity testing carries most of the quality burden.
- Category
- Botanicals and mushrooms
- Also known as
- Viburnum opulus · guelder rose · crampbark · European cranberrybush bark
- Facts checked
- November 2026
Forms and grades of cramp bark
Suppliers sell different products under the same name. Specify the one you need.
Cut bark
Dried bark in tea-cut or coarse pieces for infusions, decoctions and further extraction.
Powder
Milled bark at a stated mesh for capsules and tablets, not concentrated.
Liquid extract
Hydroalcoholic or glycerin tincture sold by herb-to-menstruum ratio, such as 1:5.
Dry extract
Concentrated extract sold by ratio, usually on a maltodextrin carrier that should be declared.
Organic or wild-harvested
Certified organic bark or wild-collected bark, with collection region recorded.
What to check on the COA
Compare each result with your own specification when the lot arrives.
- Identity
- Macroscopic and microscopic bark examination and an HPTLC fingerprint against authenticated Viburnum opulus, since bark from other shrubs and other Viburnum species can be substituted.
- Moisture
- Loss on drying for cut bark and powder.
- Heavy metals
- Lead, arsenic, cadmium and mercury by ICP-MS.
- Microbiology
- Total plate count, yeast and mold, E. coli and Salmonella.
- Residual solvents
- Ethanol and any other solvent used, for dry and liquid extracts.
- Pesticide residues
- Multi-residue screen, especially for cultivated bark and organic claims.
Storage, lots and expiry
Storage and shelf life
Keep cut bark, powder and dry extracts sealed in lined bags or drums in a cool, dry, dark area off the floor, since moisture and warmth invite mold and caking and light fades color and aroma. Reseal opened containers promptly. Shelf life or a retest date is set by the supplier's specification, and identity, moisture and microbiology are usually repeated before using aged stock.
Lots and expiry dates
Bark thickness, the age of the stems harvested and collection region vary between lots, so record origin, harvest season and the identity method used. Keep a retained sample from each lot for comparison if a substitution is suspected later.
Regulatory status
Facts from regulators and standards bodies, each linked to its source.
Health Canada's Natural Health Products Ingredients Database lists Viburnum opulus, with the common names crampbark and guelder rose, as an approved herbal name classed under Schedule 1 (plant or plant material).
Source: webprod.hc-sc.gc.ca (opens in a new tab)21 CFR 172.510 lists black haw bark (Viburnum prunifolium), a different species from cramp bark, among natural flavoring substances; Viburnum opulus is not named in that section.
Source: ecfr.gov (opens in a new tab)
This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.
Cramp bark suppliers
Manufacturers and distributors whose own websites say they sell it.
We are checking cramp bark suppliers now
Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.
Sell cramp bark? Request a listingFrequently asked questions
What forms of cramp bark can brands buy?
Common forms include cut bark, powder, liquid extract, dry extract and organic or wild-harvested. Ask each supplier for the specification sheet of the exact grade they quote.
What should the COA for cramp bark include?
Expect identity, moisture, heavy metals, microbiology, residual solvents and pesticide residues, each with its method, specification and result for that lot.
How should cramp bark be stored?
Keep cut bark, powder and dry extracts sealed in lined bags or drums in a cool, dry, dark area off the floor, since moisture and warmth invite mold and caking and light fades color and aroma. Reseal opened containers promptly. Shelf life or a retest date is set by the supplier's specification, and identity, moisture and microbiology are usually repeated before using aged stock.
What is the regulatory status of cramp bark?
Health Canada's Natural Health Products Ingredients Database lists Viburnum opulus, with the common names crampbark and guelder rose, as an approved herbal name classed under Schedule 1 (plant or plant material). 21 CFR 172.510 lists black haw bark (Viburnum prunifolium), a different species from cramp bark, among natural flavoring substances; Viburnum opulus is not named in that section.
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