As with any substance that interferes with nervous system functioning, anaesthetics are likely to have neural effects the duration of which extend beyond the acute loss of consciousness. Studies of recovery after anaesthesia have shown that physiological effects and psychomotor functions return to pre-anaesthesia levels within at most 90 min of the cessation of propofol administration. To date no report has been published concerning the possible longer term effects of propofol anaesthesia on higher cognitive functions such as learning, language, reasoning and planning. We evaluated a range of cognitive tasks (short and long-term memory, attention, language comprehension and planning) up to 6 h after cessation of Propofol administration, and found that this set of cognitive functions was still depressed after 3 h, but had recovered by 6 h. The results suggest that, for their security, patients should be remain in a supervised environment for at least 3 h after propofol anaesthesia, and that oral information to patients within those 3 h should be avoided.