A drug prescription assistance method in which a server (2) supplies information about a drug to a user terminal (1) via a communication network (N), wherein the method comprises: a step in which the server (2) receives patient data and prescription drug data from the user terminal (1); a step for determining, on the basis of the patient data and data on subscribers to a designated medical plan, whether the patient corresponding to the patient data is a subscriber to the designated medical plan; and a step in which, when the patient is a subscriber to the designated medical plan, the matter of whether there is a drug among the prescription drug data for which a generic drug can be substituted is determined on the basis of a database in which original drugs and the corresponding generic drugs are associated with each other, and, when the substitutable generic drug exists, data on substitutable generic drug data is transmitted to the user terminal (1).
