Adverse drug events (ADE) may increase the length of hospital stay, cause complications in the patient's clinical condition, contribute to death and increase hospital costs. The aim of this study was to apply the trigger tool methodology based on the method proposed by the Institute for Healthcare Improvement for the detection of adverse drug events in an intensive care unit, assessing the incidence of event and the feasibility of incorporating this practice into the unit. After the development of a trigger list, a retrospective review was carried out on a random sample of 10 patient records / month, among patients over 18 years of age, of both sexes, who were hospitalized in the intensive care unit of the study hospital. The incidence of patients with adverse drug events was 15%, and the rate of ADE was 15.8 ADE / 100 medical records, with most (85%) of the events categorized as temporary damage requiring intervention. The main therapeutic classes involved in adverse events were antibiotics, anticoagulants, sedatives and hypoglycemic agents. The main advantage of the methodology was the ability to detect more adverse drug events than the voluntary notification, methodology present at the institution at that time.