An apparatus (10) for the automatic preparation of a drug consisting of at least two components comprises a first container (12) for a first component, a second container (14) for a second component, a third container (16) to receive the prepared drug, an intermediate container (27) for the preparation of the drug, connected both to the third container (16) and also, by means of valve means (34, 36) selectively openable and closable, to the first container (12) and to the second container (14). The apparatus (10) also comprises an intake/injection device (20) able to be activated in intake mode to take in dosed quantities of the first and second component inside the intermediate container (27), and activated in injection mode to transfer the prepared drug from the intermediate container (27) to the third container (16), and an electronic control unit (40) suitable to manage automatically and in a coordinated manner the selective activation of the valve means (34, 36) and the intake/injection device (20).
