With a global increase of colorectal cancer, inflammatory bowel disease and other colon-related illnesses, advanced technologies are needed for imaging of the colon and localized drug delivery. Optical colonoscopy is the gold standard for imaging of the colon. However, existing colonoscopy approaches have a high adenoma misdiagnosis rate, which can be lethal for patients. This article reviews the emergence of virtual colonoscopy, dye-based chromoendoscopy, electronic chromoendoscopy and capsule endoscopy in diagnosis. Flexible spectral imaging colour enhancement, the use of second-generation capsule endoscopy and i-scan were described. Moreover, a drug delivery system using capsule endoscopy was discussed. Finally, this review includes market analyses of commercial products, clinical trials and future prospects of colonoscopy devices. K E Y W O R D Scolonoscopy, diagnostics, drug delivery, endoscopy, sensors