The effects of intravenous atropine 0-6 mg alone, metoclopramide (Maxolon) 10mg alone and atropine 0-6 mg and metoclopramide 10 mg in combination, on the lower oesophageal sphincter (LOS) were studied in three groups of normal human volunteers. Atropine decreased the LOS pressure by an average of 8 cm H2O (P less than 0-001), whereas metoclopramide increased the LOS pressure by a mean of 29 cmH2O compared to basal values (P less than 0-001). In contrast, no change in sphincter tone was noted following injection of atropine-metaclopramide mixture. These findings are relevant to the pre-operative preparation of patients presenting for emergency anaesthesia, since gasgro-oesophageal reflux and pulmonary aspiration of acid gastric content continues to be a significant cause of morbidity and mortality.