The peristaltic reflex represents the basis of peristalsis and has two components, ascending contraction above and descending relaxation below the site of distension. Studies of the two components of the reflex in the human oesophagus performed by concurrent monitoring of oesophageal body and lower oesophageal sphincter (LOS) motility are lacking. We investigated the peristaltic reflex in eight healthy volunteers (aged 19-25 years; five male, three female) by two series of eight graded (3-10 mL) balloon distensions performed 11 cm above the LOS, monitoring motor activity in the oesophageal body both above and below the balloon and in the LOS (sleeve sensor). During balloon distension both ascending contraction, as assessed by contractile activity above the balloon, and descending relaxation, as assessed by LOS relaxation, increased linearly with increasing inflation volumes (r = 0.6 and r = 0.8, respectively, both P < 0.0001). The threshold for descending relaxation was lower than that for ascending contraction. The contractile response of the body below the balloon was always lower than above the balloon and occurred with a higher (P < 0.05) frequency at 6 and 7 mL compared to 3, 4 and 10 mL. After balloon deflation an oesophageal contraction, usually accompanied by an LOS contraction, occurred with increasing frequency as the balloon volume increased. Our experimental model allows detailed assessment of the two components of the peristaltic reflex in the human oesophagus in vivo and should prove useful in future studies on the physiology and pathophysiology of this reflex.