['We aimed to investigate the diagnostic applications of capsule endoscopy examination patients in obscure gastrointestinal bleeding and to analyze the etiology of obscure gastrointestinal bleeding in patients of different ages.', 'A total of 385 patients with obscure gastrointestinal bleeding, aged 17-91 years, were assigned into three groups as: elderly (>65 years), middle-aged (41-65 years) and young adults (17-40 years). Gastrointestinal examinations were carried out in each participant with the use of a capsule endoscopy diagnostic system.', 'Overall, the detection rates for positive capsule endoscopy findings in the elderly, middle-aged and young adult groups were 66.94%, 62.29% and 61.80%, respectively, and the diagnostic rates were 48.76%, 45.14% and 53.93%, respectively. No significant difference existed in either rate between the different age groups. The commonest pathological changes detected were vascular malformations, intestinal tumors, Crohn’s disease, non-specific enteritis, and small intestine ulcer, but the distribution of these causes for obscure gastrointestinal bleeding varied between the different age groups. The top three common reasons for obscure gastrointestinal bleeding in the elderly group were vascular malformations, small intestine ulcers and small intestine tumors, while in the middle-aged group vascular malformation, small intestine tumor and non-specific enteritis were the most common. The young adults were most likely to have Crohn’s disease, small intestine tumors or non-specific enteritis.'] Does capsule endoscopy examination identify different leading causes of obscure gastrointestinal bleeding in patients of different ages?