To understand the cause and prognosis of your constipation, you must “peek” at your stool and record its traces. In medical imaging, there is a test called a colonic transport test, which is a test that records and understands the movement of stool in the colon by using colonic markers to assess the function of the colon. Through the colon transport function test, we can observe the whole process of food entering from the mouth to the anus, so as to determine whether the colon function is damaged and the severity of the damage. I. Examination requirements and procedures 1. Patients should stop using various laxatives and other drugs affecting gastrointestinal motility three days before the examination. 2. Take one capsule containing colon markers by mouth after breakfast on the same day, and maintain the same daily eating habits during the examination. 3, the next morning (24 hours) to take abdominal flat film, after 48 hours, 72 hours of continuous filming, a total of 3 abdominal flat film. Second, the significance of the examination 1, to determine whether there is impaired colon function and the prognosis of constipation treatment. In normal people, the colon passage time is ≤33 hours, and if the remaining marker is >20% at 72 hours, the colon function is impaired. 2.Further analysis of the area of impaired colonic function according to the marker residence site. Generally, constipation is classified into three types, such as colonic weakness, outlet obstruction and mixed colonic weakness/exit obstruction, according to the characteristics of marker distribution.