Since its first description, the acute respiratory distress syndrome (ARDS) has been acknowledged to be a major clinical problem in respiratory medicine. From July 2015 to July 2016 almost 300 indexed articles were published on ARDS. This review summarises only eight of them as an arbitrary overview of clinical relevance: definition and epidemiology, risk factors, prevention and treatment. A strict application of definition criteria is crucial, but the diverse resource-setting scenarios foster geographic variability and contrasting outcome data. A large international multicentre prospective cohort study including 50 countries across five continents reported that ARDS is underdiagnosed, and there is potential for improvement in its management. Furthermore, epidemiological data from low-income countries suggest that a revision of the current definition of ARDS is needed in order to improve its recognition and global clinical outcome. In addition to the well-known risk-factors for ARDS, exposure to high ozone levels and low vitamin D plasma concentrations were found to be predisposing circumstances. Drug-based preventive strategies remain a major challenge, since two recent trials on aspirin and statins failed to reduce the incidence in atrisk patients. A new disease-modifying therapy is awaited: some recent studies promised to improve the prognosis of ARDS, but mortality and disabling complications are still high in survivors in intensive care. Definition and epidemiologySince its first description by ASHBAUGH et al. [1] in 1967, the acute respiratory distress syndrome (ARDS) has been widely recognised as a major clinical problem worldwide, carrying a high morbidity and mortality burden [2][3][4]. Although the recent Berlin definition [5] is probably much better than previous ones, there is still a high variability in both epidemiology and clinical outcomes in diverse healthcare settings [4]. In fact, the incidence of ARDS ranges from 1.5 cases per 100 000 [2] to nearly 79 cases per 100 000 [3], with European countries reporting a lower incidence than USA [6]. Moreover, studies from Brazil reported incidence rates ranging from 1.8 to 31 per 100 000 [7,8].Although the overall survival rate is improving [9, 10], there is a notable difference when considering in-hospital mortality over several observational studies [2][3][4][8][9][10][11]. This may be explained by differences in risk factors, availability of diagnostics, ability to recognise ARDS and some selection biases affecting clinical trials [12]. Recently, a large international observational study (the LUNG SAFE trial) evaluated the incidence of ARDS across 459 intensive care units (ICUs) in 50 countries [13]. To assess the clinical recognition of ARDS according to the latest definition, any patient inclusion into the trial was made through a computer algorithm following the Berlin criteria [5], and then compared to the diagnosis made by the attending physicians. Among 4499 patients who developed acute hypoxaemic respiratory failure, ARDS occurred in 10.4% of t...