A system for controlling means for injecting anesthesia or sedation agents in an intravenous anesthesia or sedation mode with a concentration or mass flow rate target, into a patient, for inducing and maintaining this anesthesia or this sedation, the means for injecting anesthesia agents comprising first means for injecting a hypnotic agent and second means for injecting a morphinomimetic agent, comprising: - means for acquiring a signal representative of the electrocortical activity of the patient, - means for analyzing this signal in order to extract therefrom an anesthetic depth signal, - means (4, 5, 6) for tracking the value and time-dependent evolution of this anesthetic depth signal; the means (4, 5, 6) for tracking the value and time-dependent evolution of this anesthetic depth signal being associated with means (4, 5, 6) for computing control signals for controlling the first and the second means for injecting the hypnotic and morphinomimetic agent, in order to: - automatically bring the anesthetic depth signal below a target value for at least 30 seconds during a phase for inducing the anesthesia, the phase for inducing the anesthesia being the period between the beginning of the administration of the agents and the maintaining of the anesthetic depth signal at least 30 seconds below the target value, then - automatically regulating this one in a closed loop in a predetermined range during a phase for maintaining the anesthesia; and in that the means for computing commands for controlling the injection means comprise: - means for inputting by an operator a type of anesthesia induction selected from a set of induction types which differ by the initial concentration of hypnotic agent, comprising means for determining the initial concentration of hypnotic agent, with which is associated a predetermined initial concentration of morphinomimetic agent depending on the selected type of induction, and - means for determining intermediate target values for the anesthetic depth signal in order to define plateaus during the induction phase. - means for acquiring a signal representative of the electrocortical activity of the patient, - means for analyzing this signal in order to extract therefrom an anesthetic depth signal, - means (4, 5, 6) for tracking the value and time-dependent evolution of this anesthetic depth signal; - automatically bring the anesthetic depth signal below a target value for at least 30 seconds during a phase for inducing the anesthesia, the phase for inducing the anesthesia being the period between the beginning of the administration of the agents and the maintaining of the anesthetic depth signal at least 30 seconds below the target value, then - automatically regulating this one in a closed loop in a predetermined range during a phase for maintaining the anesthesia; - means for inputting by an operator a type of anesthesia induction selected from a set of induction types which differ by the initial concentration of hypnotic agent, comprising means for determining the initial concentration of hypnotic agent, with which is associated a predetermined initial concentration of morphinomimetic agent depending on the selected type of induction, and - means for determining intermediate target values for the anesthetic depth signal in order to define plateaus during the induction phase.