 Data will be collected at participating centres on two days, one between 11-15Jan2016 and one between 6-10Jun2016. Hospitals will be able to choose locally which two days. On those days investigators from the local Microbiology andor Infection Prevention teams will screen all patients on pre-identified wards, who have been admitted for 72 hours, for hospital-onset diarrhoea. For all patients that meet the definition of hospital-onset diarrhoea their medical notes and charts will be reviewed, to ascertain potential causes and how they have been managed. 