The efficacy of Entonox as a supplement to local anaesthesia for minor surgical procedures was studied. Eighty-five patients undergoing surgery for the incision and drainage of a subcutaneous abscess using a local anaesthetic were involved in a trial to ascertain the level of pain associated with such procedures and to investigate the possibility of using on-demand Entonox to supplement the local anaesthesia provided. Patients received either the standard local anaesthesia, or, alternatively, the local anaesthesia was supplemented with oxygen or Entonox via on-demand apparatus. Patients indicated on three linear visual analogue scales their pain, anxiety and total discomfort, and also on a cartoon pain rating scale, at different stages during the operation. Results showed that there was no statistically significant reduction in pain provided by the Entonox, despite general patient approval. Both oxygen and Entonox showed some anxiolytic properties. Pure oxygen was also seen to produce a rise in heart rate, while both gases (pure oxygen and Entonox) caused an increase in diastolic blood pressure. It was also seen that the patient's short term memory of the pain experienced was unaffected by pure oxygen or Entonox.