The present experiment evaluated the quality of macroscopic images and the mean time of capsule passage through different sections of the gastrointestinal tract in dogs subjected to different preparation protocols before capsule endoscopy. In the first examination, the colonoscopy preparation protocol was applied, and in the second examination, the animals were administered macrogol. The study revealed that macrogol administration before capsule endoscopy significantly improved the quality of macroscopic images. The colonoscopy preparation protocol may not support accurate visualization of the large bowel mucosa and, in selected patients, also the small bowel mucosa. Macrogol administration had no effect on capsule transit time through the alimentary canal. Capsules used in endoscopic evaluations of the small bowel in humans may have limited applications in macroscopic examinations of large bowel mucosa in dogs.