"[Plin. Nat. 22.31.] - THE PICRIS; ONE REMEDY. THE THESION; ONE REMEDY.
The picris derives its name from its intense bitterness, as we have previously stated. The leaf of it is round; it is remarkably efficacious for the removal of warts.
The thesium, too, has a bitterness not unlike it: it is a powerful purgative, for which purpose it is employed bruised in water.”
(The Natural History. Pliny the Elder. John Bostock, M.D., F.R.S. H.T. Riley, Esq., B.A. London. Taylor and Francis, Red Lion Court, Fleet Street. 1855.)