AIM: To study the prolonged colonic motility under normal conditions with a novel capsule-style microsystem and to assess its clinical significance.METHODS: A single use telemetry capsule (10 mm in diameter, 20 mm in length) embedded with a pressure sensor was ingested by the subjects. The sensor is capable of transmitting colonic pressure wirelessly for more than 130 h. The time of capsule entering the segmental colon was detected by ultrasound. The ultrasonic electrodes were mounted on the surface of the ileocecum and navel and at the junction of the left and rectosigmoid colon of the subjects in sequence,which were identified by abdominal X-rays with radiopaque markers. To verify the accuracy and reliability of ultrasonic detection of telemetry capsules at key points of colon, the segmental colonic transit time was simultaneously recorded by using radiopaque markers.RESULTS: The signal lamp showed that all recorders could receive the radio signal transmitted by the telemetry capsule. The X-rays showed that all telemetry capsules were detected successfully when they were passing through the key points of colon. There was a significant correlation between the transit results obtained by ultrasonic detection or by radiopaque markers. Colorectal recording was obtained from 20 healthy subjects during 613 h (411 h during waking, 202 h during sleep). Compared to waking, the number of pressure contractions and the area under pressure contractions were significantly (P ＜ 0.05) decreased during sleep (21 ± 5 h-1 vs 15 ± 4 h-1, 463 ± 54 motility exhibited significant regional variations both in the circadian behavior and in response to waking and meal.CONCLUSION: The capsule-style micro-system is reliable and noninvasive, and may represent a useful tool for the study of physiology and pathology of colonic motor disorders.