Objective: To investigate the effects of using propofol for medium and long-term sedation on mortality and length of intensive care unit (ICU) stay of critically ill adult patients. Design: Randomised controlled studies comparing propofol with an alternative sedative agent in critically ill adult patients were included without language restriction from the Cochrane Controlled Trial Register (2007 issue 3), EMBASE, and MEDLINE databases (1966 to 1 December 2007). Two reviewers reviewed the quality of the studies and performed data extraction independently. Measurements and results: Sixteen randomised controlled studies with a total of 1,386 critically ill adult patients were considered. Nine of the pooled studies (56%) limited the doses of propofol infusion to