The medication error can or not injure the patient, although to be a evitvel act, not being trustworth only to the professional of nursing, also englobando patient and consuming, among others professional of health. The correct behavior of the professional is to be always alert the possible reactions and, after managed the medication, this it must immediately be registered in the register of the patient, making possible the discovery of the error and the accomplishment of specific interventions that can diminish or prevent possible complications or more serious consequences. The ethical principles that the nursing professionals follow always must be remembered and are related with the veracity, beneficence, ability, justice and the allegiance for one practical one holds in agreement to the rights of the patients. When academics we are instructed and we attempt against in them in the accomplishment of the 5 certainties, with the purpose for the prevention of medication errors, that are related closely: Certain patient, certain Medicine, certain Dose, certain Way and Alias process. In accordance with the ethics code exists penalties for neglects, ineptitude and lack of responsibility of the nurse before its action stops with the patient in the hospital institution