# Glauber’s salt

**Sal mirabile*, the wonderful salt*

**Known today as.** Sodium sulfate, crystallised from spring water and from the residue of making spirit of salt.

Kind: Mineral

## What was it used for?

A gentle purge, and in the chemists’ hands a remedy for nearly everything.

## What does modern science say?

A laxative, long since replaced.

## Pharmacognosy and toxicology

- **sodium sulfate decahydrate**: 

**Mechanism.** An osmotic laxative: the sulfate is barely absorbed and holds water in the bowel, giving a watery stool in one to three hours; the same principle, with magnesium, is the Epsom salt, and the same salt is in the bowel-cleansing solutions before colonoscopy. Glauber, who found it in a spring near Vienna in 1625, thought it the universal medicine; it is a reliable purge and no more.

**Dose.** 10–30 g purges; repeated use loses water and salts; the sodium load matters in heart failure.

**Standing.** In the pharmacopoeias; a component of licensed bowel-preparation solutions (e.g., sodium picosulfate with magnesium citrate, or sulfate-based preparations).

## What lore surrounds it?

Johann Rudolf Glauber drank from a spring near Vienna while ill with fever, recovered, found the salt in its water, and named it the wonderful salt.

## Sources

- Glauber, J. R. (1658). *Tractatus de natura salium*.
- Rex, D. K., et al. (2010). “A randomized clinical study comparing reduced-volume oral sulfate solution with standard 4-liter sulfate-free electrolyte lavage solution as preparation for colonoscopy.” *Gastrointestinal Endoscopy* 72.

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*Glauber’s salt.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-09-30. The Thinking Press. https://thethinkingpress.org/materia-medica/glaubers-salt

Historical description, not medical advice.