With experience and training the colonoscope can be a very effective tool in the screening and diagnosis of colorectal cancer. However, the colonoscope most commonly used today has changed very little in the last three decades. It is not without its problems, including a risk of perforation and significant patient discomfort, especially associated with loop formation. Furthermore, loop formation may prevent a complete colonoscopy from being performed in certain patients. In order to avoid looping formation of the colonoscopy and develop a better colonoscope it is necessary to understand the generic principle that results in the looping phenomenon. Loop formation is caused by three factors including the natural characteristic of the colon, the flexible nature of the insertion tube and the impact of frictional force on deformation of intestinal walls and mesenteries. We scientifically analyse loop formation by Kirchhoff's slender rod model, and present a review of the state-of-the-art of technologies that are being promoted as a way to address the problems of the colonoscope.