By using three different Gastric Preparation of Magnetic-controlled Capsule Endoscopy, the investigators hope to find out the optimal gastric preparation plan.

It is a prospective, single-blind, randomized controlled trial. Patients who were conducted by Magnetic-controlled Capsule Endoscopy at Changhai Hospital will be randomly allocated into three different Gastric Preparation group before the procedure. It include clear water group which patient only drink 1000ml clear water before checking; simethicone group which patient drink 950ml clear water and 15ml simethicone before checking; simethicone combined with pronase group which patient drink 900ml lear water and 15ml simethicone and 20，000iu pronase before checking. The result were got from a relevant professional physician's blinded independent image-reading.

Inclusion Criteria:

• Adult patients aged 16-75 years, who were scheduled to undergo a Magnetic-controlled Capsule Endoscopy, were eligible for this study.

Exclusion Criteria:

• Dysphagia or symptoms of gastric outlet obstruction, suspected or known intestinal stenosis, overt gastrointestinal bleeding, history of upper gastrointestinal surgery or abdominal surgery altering gastrointestinal anatomy, or postabdominal radiation;
• Congestive heart failure, renal insufficiency, under therapeutic anticoagulation, in poor general condition (American Society of Anesthesiologists class III/IV), claustrophobia, metallic parts, a pacemaker or other implanted electromedical devices, artificial heart valves;
• Pregnancy or suspected pregnancy;
• Exclusion criteria for standard magnetic resonance imaging (MRI) examination such as the presence of surgical metallic devices, even though its low magnetic field would technically not interfere with such devices;
• Currently participating in another clinical study.