Confocal laser endomicroscopy (CLE) is a newly developed endoscopic technique. The most commonly used fluorescent substance is Fluorescein sodium.The plasma half-life of fluorescein is 11 minutes. A recent test estimated that fluorescein-based CLSM(confocal laser scanning microscopy) of the upper-GI tract of pigs delivers the best contrast and image quality within the first 8 minutes after injection of fluorescein .However, despite its increasing use in clinical examination,there are no data on contrast dynamics and image quality over time after injection of the fluorescein sodium in the inspection of gastrointestinal tract of human being.

Inclusion Criteria:

• These subjects will include male or female aged between 18 and 60 years with indications for upper-endoscopy ,but without serious gastritis and other serious stomach lesions

Exclusion Criteria:

• Complications such as gastric and/or duodenal peptic ulcer, stenosis
• Esophageal, gastric or duodenal cancer or other malignancy
• History of stomach surgery
• A history of bronchial asthma, or known allergy to fluorescein.
• Pregnant or breast-feeding (for females)
• Below 18 or above 60 years of age
• Severe comorbidities ( e.g. such as renal failure, congestive cardiac failure, liver cirrhosis).

patients without any disease of heart,liver or kidney;patients without serious gastritis and other serious stomach lesions.