Glaucium grandiflorum, the great-flowered horned poppy, is a species of flowering plant in the horned poppy genus which is native to the Middle East.
The species is a perennial flowering plant which has scalloped, blue-gray leaves. It flowers in the summer and fall with orange-red flowers that are in diameter. These flowers are on long stems which extend above the plant's foliage. The seed pods ripen in late summer.
Glaucium grandiflorum grows and can have one or more main stems. These stems are branched, and are covered with rather dense hairs. The petals are long. There are numerous stamens with anthers in length. Their filaments are monotonic in the upper half and broadened in the lower half. The pedicels, when fruiting, can be up to long, and are erect or contorted and hairy. The stigma are broad.
Numerous alkaloids have been isolated from the plant, including norchelidonine, dihydrochelerythrine, 8-acetonyldihydrochelerythrine, protopine, allocryptopine, corypalmine, and tetrahydropalmatine.
Glaucium grandiflorum has two accepted infraspecific varieties:
Glaucium grandiflorum has a distribution from the Eastern Mediterranean to Iran.
Glaucium grandiflorum is found in disturbed habitats and shrub-steppes. It is found in the Irano-Turanian floristic region and is a glycophyte.