AbstractThe rectal electrical activity recorded by electrorectogram (ERG) was studied in 22 chronically constipated subjects and 16 healthy colunteers. The latter had a mean (±SD) age of 42.6±8.5 years; 10 were men and 6 women. Of the 22 constipated patients, 14 had inertia‐type age 38.4±12.2 years. The rectal electrical activity was recorded by a silver‐silver chloride electrode situated 1 cm from the tip of a 6 F catheter, which was applied to the rectal mucosa by suction. At least four recording sessions of 120 minutes each were performed for each individual. In normal volunteers, regular and reproducible pacesetter potentials (PPs) were recorded with a mean frequency of 2.8±0.8 cycles/min (cpm), amplitude 2.1±0.8 mV, and velocity 4.6±0.8 cm/sec. They were followed randomly by action potentials (APs). In IC patients the PPs were so infrequent that in most cases half an hour would have elapsed without recording a PP; the mean frequency was 2.4±0.2 cycle/60 min, amplitude 0.92±0.02 mV, and velocity 4.1±0.6 cm/sec. APs were not recorded in 10 patients during the recording time; in two patients they were occasional. In OC subjects regular and reproducible PPs were recorded with a higher frequency (p<0.01) and velocity (p<0.05) than normal. Two ERG patterns were identified in those with chronic constipation: bradyrectia and tachyrectia. The former was recorded in the IC subjects and the latter in OC subjects. It is concluded that ERG is a technique by which electromechanical activity is recorded. It is noninvasive and nonradiologic, and it can be included as an investigative tool for rectal detrusor disorders.