[4] In the summer when the mature plant may have a height of , it bears sweetly scented pink or white flowers.

[6] The plant is consumed as food by the larvae of some Lepidoptera (butterfly and moth) species, including the grey pug.

Valerian is considered an invasive species in many locations outside its natural range, including the U.S. state of Connecticut where it is officially banned,[7] and in New Brunswick, Canada, where it is listed as a plant of concern.

[23] The European Medicines Agency (EMA) approved the health claim that valerian can be used as a traditional herb to relieve mild nervous tension and to aid sleep; the EMA stated that although there is insufficient evidence from clinical studies, its effectiveness as a dried extract is considered plausible.

[24] The American Academy of Sleep Medicine's 2017 clinical practice guidelines recommended against the use of valerian in the treatment of insomnia due to poor effectiveness and low quality of evidence.

[30] John Gerard's Herball, or Generall Historie of Plantes, first published in 1597, states that his contemporaries found valerian "excellent for those burdened and for such as be troubled with croup and other like convulsions, and also for those that are bruised with falls".

He says that the dried root was valued as a medicine by the poor in the north of England and the south of Scotland, such that "no brothes, pottages or phisicalle meates are woorth [worth] anything if Setwall [valerian] were not at one end".

[31][32] The 17th-century astrological botanist Nicholas Culpeper thought the plant was "under the influence of Mercury, and therefore hath a warming faculty".