Plant Family
Euphorbiaceae
The spurges — a huge, milky-sapped family that gave the world rubber, cassava, castor oil, ricin, and one approved drug.
One of the largest flowering-plant families, defined by irritant milky latex. Economically enormous, chemically dangerous, and the source of the proanthocyanidin drug crofelemer.
6 Notable Members
Overview
The Spurge Family
Around 7,500 species spanning tiny weeds, cactus-like desert succulents and tropical timber trees, held together by a single unmistakable character: milky latex, which seeps from any break in the tissue and is, in most of the family, an irritant. In Euphorbia itself the flower is not a flower at all but a cyathium — a cup of fused bracts holding reduced male flowers around one female — an arrangement unique to the genus.
The family’s economic weight is hard to overstate: natural rubber, cassava as a staple for hundreds of millions, castor oil, tung oil and the poinsettia trade all come from it. Its medical weight is much smaller, and its toxicological weight is very large indeed.
Shared Traits
How to Recognise It
In Practice
Medical Significance
The family’s clearest medical contribution is recent, precise, and belongs to dragon’s blood. The red sap of Croton lechleri yields an oligomeric proanthocyanidin that was developed into crofelemer — an FDA-approved antidiarrhoeal, and one of very few botanical drugs to complete that path. It blocks two intestinal chloride channels, is minimally absorbed, and works locally in the gut. The sap also contains taspine, an alkaloid with documented wound-healing activity that accounts for the traditional use of the latex on cuts.
Elsewhere the family’s uses are largely historical and largely purgative. Croton oil from Croton tiglium was a drastic cathartic abandoned as unacceptably violent. Castor oil remains in use as a stimulant laxative — the one gentle thing this family reliably offers. Euphorbia peplus sap, long used as a folk remedy for skin lesions, gave rise to ingenol mebutate, a licensed treatment for actinic keratosis later withdrawn over safety concerns.
Treat the latex of any euphorb as harmful until proven otherwise. The sap of many species contains phorbol esters — potent skin and mucous-membrane irritants and, notably, laboratory tumour promoters. Contact causes burning and blistering; eye exposure can cause severe keratitis and lasting damage, and is a recognised ophthalmic emergency.
Two further hazards are specific and serious. Ricin, from the castor bean, is among the most toxic proteins known; castor oil is safe because the toxin stays in the seed cake. Cassava is cyanogenic and requires proper processing — inadequate preparation causes cyanide poisoning and the paralytic disorder konzo. Dragon’s blood sap is a benign exception within the family rather than a representative of it, and even there the evidence is for the standardised drug rather than raw sap.
Phytochemistry
Characteristic Chemistry
Diterpene esters are the family signature — phorbol esters of the tigliane, ingenane and daphnane types, responsible for both the irritancy and the tumour-promoting activity. Alongside them sit cyanogenic glycosides (linamarin in cassava), ribosome-inactivating proteins (ricin), alkaloids including taspine and ricinine, and the cis-polyisoprene that is natural rubber.
Croton lechleri is chemically atypical for the family: its dominant fraction is condensed tannins — catechin, epicatechin, gallocatechin and epigallocatechin, and the proanthocyanidin oligomers built from them — which is why it behaves as an astringent rather than an irritant.
Beyond the Database
Also in This Family
Notable members without a monograph yet.
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