California poppy

It has been also used in natural medicine.

An excerpt from the article 17 facts about California poppy

Various parts of the plant have been used to repel lice, to treat headaches and toothaches, among other things. The plant has been found to have sedative properties.

Some studies suggest that California poppy may help with sleep disorders by enhancing the response of GABA (gamma aminobutyric acid) - one of the major neurotransmitters involved in sleep regulation.