A device for packaging, conserving, and extemporaneously preparing a plurality of active principles, including a reservoir having a compartment for containing a volume of liquid, the reservoir including a neck defining a dispenser opening; a head that is movable relative to the reservoir between a first distal position for conservation and a second proximate position for preparation; a leaktight closure mechanism; and a rupture mechanism for rupturing the closure mechanism. The closure mechanism is formed by a blister that contains at least two active principles and has at least two compartments, each compartment containing an active principle. The blister is fastened on the neck of the reservoir so as to close it, such that after opening the blister by the rupture mechanism, the active principles enter into contact with the liquid and dissolve therein.