# Manna (Fraxinus ornus)

*Calabrian manna*

**Known today as.** The dried sap of the manna ash, *Fraxinus ornus*, of Calabria and Sicily.

Kind: Plant

## What was it used for?

The gentlest purge, for children, women with child, and the delicate.

## What does modern science say?

Mannitol, a mild osmotic laxative still used in medicine, takes its name from it.

## Pharmacognosy and toxicology

- **mannitol**: 40–60 per cent of the dried exudate
- **mannotriose and stachyose**: oligosaccharides
- **fraxin**: a coumarin

**Mechanism.** The dried sap of the manna ash, *Fraxinus ornus*, tapped in Sicily: its mannitol is not absorbed from the gut and holds water osmotically in the bowel, a gentle laxative, which is exactly how mannitol is still used intravenously to draw water from the brain.

**Dose.** Safe; 20–60 g purges; wind and bloating in excess.

**Standing.** In the Italian and French pharmacopoeias into the twentieth century; mannitol itself is a WHO essential medicine.

## What lore surrounds it?

The tree’s common name is itself folklore: from about 1400, observers likened the sweet sap from its bark to the biblical manna that fed the Israelites in the wilderness, and the comparison stuck, naming the tree in English, Italian, and Spanish alike. Mannitol, the sugar alcohol first isolated from the sap, carries the name on.

## What did the older authorities say?

**Pliny.** In his account of the frankincense harvest, Pliny names the grades of the gathered gum: the drop that has “hung suspended in globular drops is known to us as ‘male’ frankincense,” the most esteemed is “that which is mammose, or breast-shaped,” the Greeks call the large lumps stagonia and atomus and the smaller pieces orobia, and “the fragments which are broken off by shaking the tree are known to us as manna.” The word, in Pliny, is thus a grade of frankincense crumb, not the sweet exudation of the later pharmacies. He adds that drops are still found “which weigh one-third of a mina.”

## Sources

- Grieve, M. (1931). *A Modern Herbal*.
- Wikipedia, “*Fraxinus ornus*.”
- Pliny the Elder, *Natural History* 12.32, trans. J. Bostock & H. T. Riley (1855), Perseus Digital Library.
- Wichtl, M. (2004). *Herbal Drugs and Phytopharmaceuticals*, 3rd ed., “Manna.”
- WHO (2023). *Model List of Essential Medicines*, “Mannitol.”

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

Historical description, not medical advice.