The advantages of the benzodiazepines as oral premedicants are: clear anxiolytic and sedative effect; less clear amnesic action which may prevent the recall of the time spent lying on an uncomfortable theatre trolley, but not necessarily recall of the journey to the operating theatre, or induction of anaesthesia; convenient route of administration; long duration of action of 5–8 h which simplifies timing of drug administration; adverse autonomic, hormonal and circulatory system reactions seem to be prevented, thus preventing the stress reaction even before induction of anaesthesia; anticonvulsant and muscle-relaxing actions may be of value in patients receiving local anaesthesia, or in preventing the side-effects of depolarizing muscle relaxants; nausea before and after operation may be decreased; reduced frequency of side-effects before and after operation.