大戟科属双子叶植物纲中的一个大科，有240属大约6,000种。

• 大部分为单叶，稀为复叶的，大部分互生，少数对生；有托叶，叶子的基部或叶柄上有时具有腺体。
• 花单性，雌雄同株或异株，总状、圆锥花序，或为杯状聚伞花序，花被两轮，各轮3～5枚，大多数不具花瓣，或全无花被；雄蕊从1个到10个以上不等，分离或合生；子房上位，通常3室；花盘发达，环状、杯状或分裂成腺体状，无花盘的稀少。
• 果实多为蒴果，成熟时分裂成3瓣，也有不开裂的浆果或核果；种子有丰富的胚乳。

Euphorbiaceae, the spurge family, in common English sometimes called "euphorbias", which is also the name of a genus in the family, is a large family of flowering plants with about 300 genera and 7,500 species. Most spurges are herbs, but some, especially in the tropics, are shrubs or trees. Some are succulent and resemble cacti because of convergent evolution. Laypersons may refer to euphorbias having a growth form and succulence similar to cacti as being "cactuses".