The family is cosmopolitan, occurring in temperate and subtropical climates (mostly in the northern hemisphere) like Eastern Asia as well as California in North America.

The non-fleshy fruit is usually a capsule, breaking open at maturity to release the seeds through pores (poricidal), through the partitions between the cells (septicidal), or by means of valves (valvular).

The main alkaloids found in opium, such as morphine, and codeine have huge impact on pharmaceuticals and a big importance on many countries that produce it on a large-scale including Afghanistan.

There is high genetic variability among poppy cultivars and environmental factors like wounding and methyl jasmonate treatment induce higher alkaloid production.

Challenges still remain in understanding what effects alkaloid production for pharmaceutical purposes, highlighting importance of research in this field.

[1] Thus the Cronquist system of 1981 recognised the Fumariaceae as a separate family, despite their close phylogenetic relationship to the Papaveraceae sensu stricto.

One morphological and molecular study concluded that the former family Pteridophyllaceae has a basal position with a subsequent division into two terminal clades each containing one of the subfamilies Fumarioideae and Papaveroideae, which are clearly monophyletic.

Some species, mostly those from the arctic and alpine regions, reinforce their attraction with floral fragrance (for example, Papaver alpinum smells of cloves), which in the case of Romneya drugs the insects.

In the case of Bocconia the seeds remain attached to the replums after the capsule's valves have fallen leaving their brilliant red or orange arils exposed, which attract birds to feed on them, facilitating their dispersal (ornithochory).

Seeds that lack an aril appear to be dispersed by the wind (anemochory) for capsules that open, in the other cases they are freed when the fruit decomposes.

They have adapted to arctic and alpine habitats and to arid, Mediterranean areas, many species are ruderal and segetal (growing in cornfields).

The Fumarioideae are basically found in open, rocky, alpine landscapes or vertical or overhanging cracks, while some species are ruderal or segetal.

The fossils of the late Cretaceous poppy Palaeoaster inquirenda from the Western Interior of North America occurs from 74.5 million year old deposits in the Fruitland Formation in New Mexico to 64.5 million year old deposits in the Hell Creek Formation in North Dakota.

Dehiscent fruit fossils of Palaeoaster have been found at the excavation site for the well known Tyrannosaurus rex specimen BHI 3033.

[16] The family is well known for its striking flowers, with many species grown as ornamental plants, including California poppy (Eschscholtzia californica, the California state flower), the stunning blue Himalayan poppies (Meconopsis), several species of Papaver, and the wildflower bloodroot.

Some Funarioideae have a limited use in gardening, with Lamprocapnos spectabilis ("bleeding heart"), and Pseudofumaria lutea ("yellow corydalis") commonly used.

In Great Britain, Canada, the United States, and Australia the corn poppy is worn in remembrance of World War I.