Crohn's disease (CD) is a type of chronic inflammatory bowel disease (IBD) associated with ulceration, and the main foci of the inflammation in CD patients are typically the terminal ileum and colon. However, in the upper gastrointestinal tract (GIT), including the esophagus, stomach and duodenum, inflammatory lesions are also detected as well, with a relatively high frequency (30-75%). Recent advances in imaging modalities, including endoscopy, have aided in the diagnosis of CD. Various lesions, including aphtha, erosion, ulcers, bamboojoint-like appearance and notch-like appearance, are detected in the upper GI of CD patients. Of these lesions, the bamboo-joint-like appearance in the gastric cardiac region and notch-like appearance in the second portion of the duodenum are highly specific for CD, regardless of the disease activity at other sites. These two findings, particularly a bamboo-joint-like appearance, have therefore been considered as potential biomarkers for CD. Although proton pump inhibitors (PPIs) are administered as an initial treatment for upper GIT lesions of CD, the efficacy of this treatment remains controversial. The administration of mesalazine, steroids, immunosuppressant and biologic agents is expected to be effective for treating such lesions.