The aim of this study was to develop a new method for investigation of the relation between the mechanical stimulus, the biomechanical properties and the visceral perception evoked by volume-ramp-controlled distension in the human duodenum in vivo. An impedance planimetric probe for balloon distension was placed in the third part of the duodenum in seven healthy volunteers. Distension of the duodenum was done at infusion rates of 10, 25 and 50 ml min^-1, respectively. The pump was reversed when level 7 was reached on a visual analog scale (VAS) ranging from 0-10. Distensions were done with and without the administration of the antimuscarinic drug butylscopolamine. The total circumferential tension (T_total) and the passive circumferential tension (T_passive) were determined from the distension tests without and with administration of butylscopolamine, respectively. T_total and T_passive showed an exponential behavior as function of strain (a measure of deformation). The active circumferential tension (T_active) was computed as T_total - T_passive and showed a bell-shaped behavior as function of strain. At low distension intensities, the intensity of sensation at 10 ml min^-1 was significant higher than that obtained at 25 and 50 ml min^-1. The coefficient of variation at the pain threshold for circumferential strain (average 4.34) was closer to zero compared to those for volume (8.72), pressure (31.22), and circumferential tension (31.55). This suggests that the mechanoreceptors in the gastrointestinal wall depend primarily on circumferential strain. The stimulus-response functions provided evidence for the existence of low and high threshold mechanoreceptors in the human duodenum. Furthermore, the data suggest that high threshold receptors are non-adapting.