Euphorbia serrata is a monoecious, annual herb, about 40 cm tall, erect and unbranched. On its single stem are distributed alternate, serrate, oval leaves; the characteristic serrated edge of leaves and bracts allows it to be easily distinguished from other euphorbias. The flowers, very bright green, appear in mid-spring; they are hermaphrodite. Pollination is normally carried out by dipterans. The fruit is a small dehiscent capsule. All parts of the plant contain a white and very viscous latex, from which it takes its common name.