E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Valerian (the herb).
An irresistible attraction to cats. (The word is from the Latin valre, to be well, and hence to make well and keep well.) It is an excitant, antispasmodic, tonic, and emmenagogue. The Father of Botany says:
Valerian hath been had in such veneration, that no brothes, pottage, or physical meates are worth anything, if this be not at one end.