# Borax

*Arabic *bawraq*; tincal*

**Known today as.** Sodium borate, brought as the crude salt tincal from the lakes of Tibet.

Kind: Mineral  
Toxic: yes

> **Caution.** Poisonous to children in quantity.

## What was it used for?

A flux for goldsmiths; in medicine, mixed with honey as a paint for thrush in the mouths of infants.

## What does modern science say?

Toxic in quantity, particularly to children; its use in medicines for the mouth has been abandoned, and the European Union counts it harmful to reproduction.

## Pharmacognosy and toxicology

- **sodium tetraborate**: 
- **boric acid**: 

**Mechanism.** Boron compounds are cumulative poisons of the testes and the developing child in animals; in infants, boric acid absorbed through broken skin has killed.

**Dose.** About 15–20 g of boric acid for an adult; far less for an infant.

**Standing.** Classed as toxic to reproduction in the European Union; boric acid eye washes survive at low strength.

## Sources

- Pomet, P. (1694). *Histoire générale des drogues* (English, *A Compleat History of Druggs*, 1712).
- European Chemicals Agency (2010). *Harmonised classification of boric acid and borates*.

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

Historical description, not medical advice.