To assess the incidence of diarrhoea in intensive care patients with a length of stay (LOS) greater than 3 days who were receiving any type of enteral tube feeding, and to measure the effect of implementing a bowel management protocol.A 2-year prospective audit, with an intervention after 12 months. Diarrhoea was defined as bowel activity exceeding three stools of any consistency per day, or three or more unformed stools (or 300mL) per day, for two consecutive days.A tertiary referral intensive care unit (ICU) in a large public hospital.Six hundred fifty-six consecutive patients admitted to ICU with a LOS >3 days.A bowel management protocol was implemented to address both diarrhoea and constipation.Number of patients who experienced diarrhoea during their ICU stay; number of ICU patient-days on which diarrhoea occurred.After the protocol was implemented, diarrhoea was experienced by 13% fewer patients (p=0.0002) and occurred on 8% fewer ICU days (p<0.0001).Use of an evidence-based protocol, and improved monitoring and reporting of bowel activity, can decrease the incidence of diarrhoea in ICU patients.