Herbs, annual, biennial, monocarpic perennial, perennial, or shrubby. Laticifers or elongated idioblasts present. Leaves alternate or in a basal rosette, rarely opposite or whorled, usually without stipules; leaf blade entire to compound. Inflorescences racemes, panicles, dichasia, pseudoumbels, or solitary flowers. Flowers actinomorphic, bisymmetric, or zygomorphic, always bisexual, usually 2-merous, rarely 3- or 4-merous. Calyx caducous, green or petaloid. Corolla choripetalous or quasi-sympetalous, very rarely absent. Anthers opening by slits. Ovary superior, syncarpous with 2 to several carpels; placentation parietal.
Forty genera and ca. 800 species: mainly in the N Hemisphere of both the Old and New Worlds, extending into Central and South America, a few in Africa; 19 genera (one endemic, two introduced) and 443 species (295 endemic, five introduced, one requiring verification) in China.
Many species are used medicinally due to the high content of alkaloids.
The two subfamilies recognized here are often treated as separate families.
Wu Chengyi, Chuang Hsuan & Su Ziyun. 1999. Papaveraceae. In: Wu Chengyi, ed., Fl. Reipubl. Popularis Sin. 32: 1-483, 541-545.