Rootstock and root of valerian, see also valerian root.
Quality is defined in the European Pharmacopoeia (Ph. Eur.):
HMPC - Monograph: well-established use as dry extract (DEV 3-7,4:1, extractant ethanol 40-70 %): mild nervous tension and insomnia. Also well-established use in combinations of valerian root and hop cones: insomnia. Additionally traditional-use: Valerian root cut drug and other dry extracts, liquid extracts, valerian tincture, valerian fresh plant juice and valerian essential oil: mild stress-related symptoms, sleep aid
ESCOP monograph: mild nervous tension and/or sleep disorders
Commission e-monograph: restlessness, nervous sleep disorders
Empirical medicine: nervous stomach cramps, colic and uterine spasms