Capsule endoscopy is an oral intake of a smart capsule, which is made to move and take images in the digestive tract with the help of peristalsis, so as to understand the condition of the digestive tract of the examined person and make a diagnosis of his/her condition. Indications Includes unexplained gastrointestinal bleeding, unexplained iron-deficiency anemia, suspected small bowel tumors, suspected or uncontrollable malabsorption syndromes, detection of non-steroidal anti-inflammatory drug-associated small bowel mucosal injury, and those who need to exclude small bowel disease in the clinical setting, and is also used to monitor and guide the treatment of Crohn’s disease and the development of small bowel polyposis syndromes. Contraindications Absolute contraindications: those who are ineligible for surgery or who refuse to undergo any abdominal surgery (once the capsule is retained it will be removed surgically). Relative contraindications: known or suspected gastrointestinal obstruction, stenosis and impotence; implantation of cardiac pacemakers or other electronic devices; swallowing disorders; pregnant women. Preoperative preparation Fasting is required for 10-12 hours before the examination, and bowel cleansing preparation (the same as colonoscopy preparation) is performed the night before the examination to improve the clarity of the image; an appropriate amount of expectorant can be taken half an hour before the operation to minimize the effect of foam on the field of vision. You may drink water 2 hours after taking the capsule, and you may eat a small amount of light food after 4 hours. The examination is concluded when the capsule battery is depleted or after the capsule enters the colon via the ileocecal valve. Complications of capsule endoscopy include capsule retention and aspiration into the airway. A capsule that remains in the gastrointestinal tract for more than 2 weeks after capsule endoscopy is defined as a retained capsule, and should be seen promptly for surgical or balloon-assisted small bowel removal.