Background Tricyclic antidepressants, which have multiple pharmacological influences, have a therapeutic effect in non-cardiac chest pain, but selective serotonin reuptake inhibitors have a single pharmacological effect. Aim To evaluate the acute effect of citalopram on oesophageal hypersensitivity. Methods On two separate occasions, 10 healthy subjects (seven men, mean age 25 years) with established oesophageal hypersensitivity, underwent oesophageal manometry with evaluation of mechanical and chemical sensitivity. Subjects received placebo or citalopram 20 mg i.v. in a randomized, crossover, double-blind fashion. Results Citalopram did not alter oesophageal motility. Citalopram significantly increased the threshold inducing first perception (4.6+/-0.3 vs. 6.7+/-0.4 mL, P<0.005) and discomfort (8.6+/-0.4 vs. 9.9+/-0.6 mL, P<0.01) during balloon distention. It also significantly prolonged the acid perfusion time to induce perception of heartburn (6.0+/-0.9 vs. 10.7+/-0.6 min, P<0.005) and discomfort (12.2+/-0.8 vs. 16.7+/-0.7 mL, P<0.001). Seven subjects experienced a retrosternal sensation during edrophonium provocation with placebo, and this was reduced to two of 10 after citalopram (P=0.02). Conclusions Acute administration of citalopram significantly lowers chemical and mechanical oesophageal sensitivity in oesophageal hypersensitivity, without altering the motility.