This study deals with some specific properties of the element anti- in Spanish which are generally uncharacteristic of prefixal morphemes, but which can be found, to some extent, also in other prepositional and quantitative prefixes (such as pro-, inter-, multi-, bi-, etc.). In the second part (the present article), we examine the possible prepositional or quasiprepositional use of anti- in certain constructions (e.g. un plan anti riadas en Castrovido, ley antitabaco) and we try to find explanation for the existence of analogue formations containing a quantitative prefix (e.g. casa biplanta).