Injections of lignocaine as local anaesthetic for pain control in oral and maxillofacial surgery can themselves be painful. The time of onset of anaesthesia is from 3 to 5 min. Sodium bicarbonate has been used worldwide to reduce both these drawbacks to the injection, so making procedures more acceptable. This randomised prospective trial of 100 patients aged 18-55 years who were given 3 nerve blocks (inferior alveolar, lingual, and long buccal) was designed to assess the effect of alkalinisation of the lignocaine solution with sodium bicarbonate. All patients were given 2% lignocaine hydrochloride with adrenaline 1:80,000 and 50 patients were randomly allocated to be given 8.4% sodium bicarbonate in a 1/10 dilution. Pain was measured on a visual analogue scale (VAS). No patient given the injection with sodium bicarbonate complained of pain, compared with 39/50 (78%) not given sodium bicarbonate (p<0.0001). The mean (SD) time (seconds) to onset of local anaesthesia in the group given sodium bicarbonate was 34.4 (9.8) compared with 109.8 (31.6) in the control group (p<0.001). Our results have confirmed the efficacy of the alkalinised local anaesthetic solution in reducing pain on injection and resulting in quicker onset of anaesthesia.