This study was to test an appropriate dose of fluorescein sodium which can provide high image quality to ensure endoscopy examination and have no yellow dye in the skin by a randomized blinded controlled trial.

Fluorescein sodium is one of the commonly used staining agents in confocal laser endoscopy, a device for in vivo real-time histological observation of the gastrointestinal mucosa. The conventional intravenous dosage of fluorescein sodium is in the range of 5ml to 10ml of 10% fluorescein. Image quality can be guaranteed with this range of fluorescein sodium, but yellow discoloration of the skin seriously influences daily life. This study was to test whether a lower dose of fluorescein sodium, which has minimal discoloration of skin, can provide satisfied image quality by a randomized blinded controlled trial.

Inclusion Criteria:

• Only those with normal mucosa and minor gastritis from 18 were included.
• patients with aged 18 years to 80 years
• patients with normal mucosa and minor gastritis
• willing to provide informed consent

Exclusion Criteria:

• serious coagulopathy dysfunction, severe cardiopulmonary disease, bronchial asthma, liver and kidney dysfunction, allergy to fluorescein, pregnancy women or breast feeding.
• patients with peptic ulcer, gastric cancer, remnant stomach, acute serious gastritis were also excluded.
• unwilling to provide informed consent