This is usually a small, cup-like involucre consisting of fused-together bracts and peripheral nectary glands, surrounding a ring of male flowers, each a single stamen.

The family contains a large variety of phytotoxins (toxic substances produced by plants), including diterpene esters, alkaloids, and cyanogenic glycosides (e.g. root tubers of cassava).

Twenty first century molecular studies have shown that the enigmatic family Rafflesiaceae, which was only recently recognized to belong to order Malpighiales, is derived from within the Euphorbiaceae.

[10] Amongst the oldest fossils of the group include the permineralised fruit Euphorbiotheca deccanensis from the Intertrappean Beds of India, dating to the late Maastrichtian at the end of the Cretaceous, around 66 million years ago.

[11] Some species of Euphorbiaceae have economic significance, such as cassava (Manihot esculenta), castor oil plant (Ricinus communis), Barbados nut (Jatropha curcas), and the Pará rubber tree (Hevea brasiliensis).

Although some species of the Euphorbiaceae have been used in traditional medicine,[13] as of 2019[update], there is no rigorous clinical evidence that euphorbia extracts are effective for treating any disease.

There is evidence that euphol, a tetracyclic triterpene alcohol, and the main constituent of the sap of the medicinal plant Euphorbia tirucalli, has anti-cancer activity.

Euphol also exhibited antitumoral and antiangiogenic activity in vivo, using the chicken chorioallantoic membrane assay, with synergistic temozolomide interactions in most cell lines.

[15] Numerous Euphorbiaceae species are listed on the poisonous plant database of the US Food and Drug Administration mainly because of the toxic sap.