# Sweet woodruff (Galium odoratum)

**Asperula odorata*; German *Waldmeister**

**Known today as.** *Galium odoratum*, a small woodland herb with whorled leaves that smell of new hay only once they are dried.

Kind: Plant  
Poisoning: Coumarin and the liver (https://thethinkingpress.org/materia-medica/poisons/coumarin)

## What was it used for?

A cordial and liver herb; laid among linen and hung in rooms and churches for its scent.

## What does modern science say?

The hay scent is coumarin, released as the plant dries; coumarin in quantity harms the liver, and its use in food is limited in the European Union.

## Pharmacognosy and toxicology

- **coumarin**: from melilotoside, freed on drying; up to 1 per cent
- **asperuloside**: an iridoid
- **tannins**: 

**Mechanism.** The hay scent is coumarin, released as the plant wilts; coumarin itself is not anticoagulant (that is dicoumarol, from spoiled sweet clover), but it is hepatotoxic in rats and in some people at high doses, and the European Union limits it in food. The May wine of Germany is permitted at a set level.

**Dose.** The tolerable daily intake is 0.1 mg of coumarin per kilogram (BfR); a glass of May wine is within it; headaches follow excess.

**Standing.** A flavour, regulated; no medical monograph.

## What lore surrounds it?

Steeped in white wine it makes the German *Maibowle*, the May wine of the first of May.

## What did the older authorities say?

**Gerard.** Writes that it is made up into garlands and hung in houses in summer, where it “doth very well attemper the aire, coole and make fresh the place.”

## Sources

- Gerard, J. (1597). *The Herball*.
- Grieve, M. (1931). *A Modern Herbal*, “Woodruff.”
- Abraham, K., et al. (2010). “Toxicology and risk assessment of coumarin: focus on human data.” *Molecular Nutrition and Food Research* 54.
- EFSA (2008). “Coumarin in flavourings and other food ingredients with flavouring properties.” *EFSA Journal* 793.

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*Sweet woodruff.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-09-30. The Thinking Press. https://thethinkingpress.org/materia-medica/sweet-woodruff

Historical description, not medical advice.