# Turmeric (Curcuma longa)

**Curcuma*; *terra merita*, Indian saffron*

**Known today as.** *Curcuma longa*, of the ginger family, whose root is deep yellow within.

Kind: Plant

> **Caution.** Some turmeric sold in South Asia has been adulterated with lead chromate to brighten its colour.

## What was it used for?

In European pharmacy, for jaundice and obstructions of the liver, the yellow root answering the yellow disease; a dye and a spice.

## What does modern science say?

Curcumin, its pigment, has been studied in thousands of papers, but it is poorly absorbed and unstable, and a 2017 review concluded that no properly controlled trial had shown it to work.

## Pharmacognosy and toxicology

- **curcumin**: 
- **demethoxycurcumin**: 
- **turmerone**: the oil

**Mechanism.** Curcumin reacts with many proteins in the dish but is barely absorbed and quickly cleared.

**Dose.** Gram doses are tolerated; lead chromate adulteration is the real hazard.

**Standing.** A food; no approved medicinal use.

## What lore surrounds it?

The drug-sellers’ name *terra merita*, “deserving earth,” is one guess at the origin of the word “turmeric.”

## Sources

- Pomet, P. (1694). *Histoire générale des drogues* (English, *A Compleat History of Druggs*, 1712).
- Nelson, K. M., et al. (2017). “The Essential Medicinal Chemistry of Curcumin.” *Journal of Medicinal Chemistry* 60.
- Nelson, K. M., et al. (2017). *Journal of Medicinal Chemistry* 60.

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

Historical description, not medical advice.