# Rowan (Sorbus aucuparia)

*Mountain ash, witchen*

**Known today as.** *Sorbus aucuparia*.

Kind: Plant

## What was it used for?

The berries astringent, in jellies and for scurvy.

## What does modern science say?

Raw berries contain parasorbic acid and upset the stomach; cooking removes it.

## Pharmacognosy and toxicology

- **parasorbic acid**: in the fresh berry; converted to sorbic acid on cooking
- **sorbitol**: first isolated from rowan berries in 1872
- **vitamin C**: 
- **tannins**: 

**Mechanism.** The raw berry’s parasorbic acid irritates the stomach and kidney, which cooking and drying convert to sorbic acid, the food preservative E200; the cooked berry is an astringent fruit with vitamin C, the scurvy use. Sorbitol, the sugar alcohol, was first found here.

**Dose.** Raw berries in quantity give vomiting and diarrhoea; cooked, a food.

**Standing.** A food; sorbic acid and sorbitol are its industrial legacy.

## What lore surrounds it?

The first tree against witchcraft in the British Isles: “Rowan tree and red thread / Hold the witches all in dread.” Sprigs were fixed over doors and byres and tied to cattle.

Norse myth credits the rowan with saving a god: Thor, swept away in a river of the otherworld, escaped only by grasping a rowan that bent over the water, and the Norse held this to be the source of the tree’s protective power. Its berries, each marked with a five-pointed star where the flower had been, strengthened the belief, and crosses of rowan twigs bound with red thread were worn or hung in the house, especially on May Eve.

## What did the older authorities say?

**Pliny.** Pliny treats the sorb, the fruit of the rowan's cultivated cousin, among the stored fruits of the Roman larder: “Sorb apples, too, are similarly kept in holes in the ground, the vessel being turned upside down, and a layer of plaster placed on the lid: it should be buried two feet deep, in a sunny spot; sorbs are also hung, like grapes, in the inside of large vessels, together with the branches.” Among his sixty-six artificial wines he lists one made from “cornels, medlars, sorb apples, dried mulberries, and pinenuts,” which “produce a sweet liquor of themselves.”

## Sources

- Grieve, M. (1931). *A Modern Herbal*.
- Trees for Life, on rowan mythology and folklore.
- Pliny the Elder, *Natural History* 15.18; 14.19, trans. J. Bostock & H. T. Riley (1855), Perseus Digital Library.
- Frohne, D., and Pfänder, H. J. (2005). *Poisonous Plants*, 2nd ed., “*Sorbus aucuparia*.”

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*Rowan.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-01. The Thinking Press. https://thethinkingpress.org/materia-medica/rowan

Historical description, not medical advice.