Petty spurge, a winter or summer annual broadleaf plant, is a weed of urban places such as landscaped areas and gardens preferring moist, shady locations and often occurring among shrubs and flowerbeds. It also inhabits agricultural land and is found throughout California, except for deserts and the Great Basin, to an elevation of 1000 feet (300 m). Consumption of this plant can cause digestive tract problems, and although rare, it has been reported to be fatally toxic to humans and livestock. The milky sap may cause dermatitis.

Petty spurge is a hairless, erect, light green plant, with single or branched slender stems that can grow to almost 20 inches (0.5 m) tall. Lower leaves are egg shaped, with a rounded to a slighted indented tip, 2/5 to 1-2/5 inches (1–3.5 cm) long, on a short stalk, and are either alternate to one another or almost opposite to one another with one leaf in each pair attaching a little below the other. Reduced leaves (bracts) are opposite to one another along the flowering portion of the stem. A whitish sap exudes when stems are broken.