**1. Introduction**

Gastrointestinal disorder is one of the commonly encountered problems in canine practice. Chronic disorders of small intestine of dogs are one among the major problems. Majority of the disorders can be successfully managed if diagnosed and treated earlier. If small intestine disorders are not treated appropriately, they may result in severe malabsorptive disease and death. Chronic form of intestinal disease usually disrupts the normal function of the small intestine and results in vomiting, diarrhea, weight loss, and reduced appetite [1]. Duodenal disorders like ulcers, inflammatory bowel disease (IBD), and small intestinal bacterial overgrowth (SIBO) play a major role in the small intestinal disorders [2]. Duodenal disorders are difficult to identify clinically because of the non-specific symptoms. They may or may not be identifiable through routine radiographic, ultrasonographic, or laboratory evaluation methods, because many diseases of duodenum primarily involve the mucosal surface [3]. Thus diagnosis and treatment of the duodenal disorders are challenging for the canine practitioners [4]. Duodenoscopy is an efficient way of identifying the abnormalities of proximal small intestinal mucosa including mucosal irregularities, distortion, ulceration, neoplasia, inflammation, and other mucosal disorders of the duodenum. Duodenosocopy is also useful for obtaining mucosal biopsy and duodenal juice for routine histopathological and bacteriological studies [5].
