The effects of urapidil on the haemodynamic response to endotracheal intubation were compared to that of placebo in two groups of 25 patients scheduled for general surgery. Normal saline solution or 0.4 mg.kg-1 urapidil were injected 3 min before induction of anaesthesia with 3 micrograms.kg-1 fentanyl, 0.3 mg.kg-1 etomidate and 0.1 mg.kg-1 vecuronium. Blood pressure (Pasys, Padia, Pa) and heart rate were measured continuously by servoplethysmomanometry before giving the test drug (T0), at the time when the lowest blood pressure was recorded during the three minute period between giving the drug and induction (T1), at the time when the lowest blood pressure was recorded during the three minute period between induction and endotracheal intubation (T2), at the time when the highest blood pressure was recorded immediately after intubation (T3), three minutes after intubation (T4), five minutes after intubation (T5), and at the time when the lowest blood pressure was recorded after surgery had been started (T6). It was planned to give a 25 mg urapidil dose to any patient, from either group, who had a Pasys greater than 200 mmHg for more than 60 sec. Giving urapidil lowered Pasys (T1) by 16%, whilst heart rate increased by 12%. The blood pressure peak due to endotracheal intubation was lower in those patients who had been given urapidil than in the placebo group (T3; p less than 0.05). Six patients in the latter group required the 25 mg urapidil dose, versus 2 in the urapidil group. The preventive effects of urapidil seem to be similar to those obtained with other antihypertensive agents.(ABSTRACT TRUNCATED AT 250 WORDS)