The nature of preoperative anxiety appears to vary from patient to patient, and the natural course of the condition has not been well evaluated. In clinical studies, the incidence of preoperative anxiety has varied widely, from 11 to 80%, depending on the methods used to assess it. Because there appears to be a relationship between high preoperative level of anxiety and greater surgical risk, attempts to measure and relieve presurgical anxiety seem to be of clinical significance.There are several problems with the designs and methods used in past and more recent studies of premedication. Many of the recent results were produced from studies that used a variety of more or less validated assessments, yielding variable results in different centres which can seldom be compared with each other. More accurate and generally accepted but simple assessments are needed to studying the anxiolytic effect of different premedicants.Benzodiazepines are the most popular preoperative agents because their anxiolytic effect is associated with high patient acceptance and they are devoid of significant adverse effects. However, great interindividual variation in response does occur. It is likely that new methods of administering benzodiazepines (such as by intranasal, transmucosal and rectal routes) could increase the utility of these agents.The preoperative anxiolytic effect of antipsychotics, antihistamines and barbiturates is questionable, but some opioids and especially &agr;2receptor agonists appear to have this property. However, clinically significant unwanted effects may prevent the routine use of the latter 2 drug groups.It should be noted that all patients do not automatically require pharmacological premedication. Good preoperative information, assurance and a positive attitude of hospital personnel may be the best treatment for preoperative anxiety in some cases.