F or patients diagnosed with sepsis or septic shock, an empirical broad-spectrum therapy with one or more antimicrobial agents is recommended to cover all possible pathogens (bacterial, fungal or viral agents). [1] The majority of current studies have focussed on the development and prevention of antimicrobial resistance. [2,3] Empirical antibiotic regimens should be selected based on the local resistance characteristics, the risk of development of the Objectives: The present study aimed to monitor the effects of antibiotic use under the guidance of culture and procalcitonin in patients admitted to the intensive care unit (ICU) due to sepsis or septic shock. Methods: This prospective, cross-sectional, clinical trial was conducted on patients admitted with sepsis or septic shock to Dr. Sadi Konuk Training and Research Hospital Anesthesia and Reanimation Clinic Intensive Care Unit between 01.01.2018 and 30.06.2018. For each patient a record was made of demographic data, reason for hospitalization reasons, PCT, C-reactive protein (CRP), blood leukocyte levels (WBC), lymphocyte percentages, neutrophil percentages, platelet (Plt) counts on admission, in the 72 nd hour and on the 7 th day, Acute Physiology and Chronic Health Evaluation II (APACHE II) scores at the time of hospitalization and discharge, Sequential Organ Failure Assessment (SOFA) scores and modes of discharge (exitus, recovery). The blood, tracheal aspirate, urine and/or tissue cultures of the patients were followed. The patients who met the criteria underwent DE. Results: The study included a total of 186 patients, comprising 102 (54.8%) males and 84 (45.2%) females, with a mean age of 66.64±17.6 years. DE was applied to 97 patients (52%) in the first 72 hours. Culture positivity obtained in the first 72 hours was higher in patients who underwent DE (OR=3.1, 1.6-6.5, CI=95%, p=0.001). It was seen that patients who underwent DE with culture positivity had a shorter stay in the intensive care unit (p=0.046). When the procalcitonin levels were analyzed, no statistically significant difference was found between the culture-positive DE group and the culture-negative DE group. Conclusion: In conclusion, the culture results guide the DE management in patients who are followed up with the clinical picture of infection in the intensive care unit. It is thought that PCT monitoring can be used as a guideline for the discontinuation of broad-spectrum antibiotics in culture-negative infectious patients. There is a need for more extensive studies related to this subject to investigate survival outcomes.