# Cassia, flower of (Cassia fistula)

**Fior di cassia**

**Known today as.** The sweet black pulp of the pods of *Cassia fistula*, the Indian laburnum; not the bark spice called cassia.

Kind: Plant  
Poisoning: The anthranoid purgatives (https://thethinkingpress.org/materia-medica/poisons/anthranoid)

## What did Canale use it for?

Freshly extracted, with lenitive electuary or rhubarb, in purging pills (chs. 2, 4).

## What does modern science say?

A genuine laxative, still used in Ayurvedic medicine.

## Pharmacognosy and toxicology

- **rhein**: an anthraquinone of the pulp and flower
- **sennosides**: 
- **fistulic acid**: 

**Mechanism.** *Cassia fistula*, the purging cassia: its anthranoids reach the colon unabsorbed, where bacteria free the anthrones, which stimulate the bowel wall and draw water into it, eight to twelve hours after the dose. The pulp of the pod is the drug; the flower is a milder form of the same.

**Dose.** The pulp at 30–60 g purges; griping and cramps in excess, and loss of potassium with long use.

**Standing.** In the Indian and Unani pharmacopoeias; no EMA monograph; senna has replaced it in Western practice.

## What lore surrounds it?

Folkard notes of the Cassia Fistula, the Indian laburnum whose pulp is the flower of cassia of the old shops, that “a sugary substance extracted from the pulp between the seeds is commonly used as a laxative,” and that Gerarde “says this pulp of Cassia Fistula, when extracted with Violet water, is a most sweet and pleasant medicine, and may be given without danger to all weak people of what age and sex soever.” He attaches the Chinese moon-tree to the name: “in the middle of the Moon there grows a Cassia-tree, at the foot of which is a man who is endeavouring continually to fell it,” Kang Wou, condemned by a Geni to cut it down for ever.

## Sources

- Folkard, R. (1884). *Plant Lore, Legends, and Lyrics*, “Cassia-Tree.” Project Gutenberg #44638.
- Danish, M., et al. (2011). “*Cassia fistula* Linn.: a comprehensive review.” *Journal of Natural Product and Plant Resources* 1.
- Bruneton, J. (1999). *Pharmacognosy, Phytochemistry, Medicinal Plants*, 2nd ed., “Anthracene derivatives.”

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

Historical description, not medical advice.