Sixty-nine patients undergoing regional anaesthesia were premedicated with either lorazepam (1, 2, 3 or 5 mg), diazepam (5 or 10 mg), pentobarbitone (50 mg) or placebo given i.v., on a double-blind, randomized basis. A simple yet rigorous protocol was used to test the effect of these drugs on anterograde recall. Lorazepam 3 and 5 mg was found to affect anterograde recall significantly. None of the other drugs tested affected recall.