Study was designed to evaluate efficacy of OsrhCT and Dimethicone emulsion before upper endoscopy on visibility of gastric mucosa.

A total of 336 subjects (both male and female) are expected to be enrolled in this trial.

This is a monocentric, double-blind, randomized study involving 336 patients indicated for diagnostic upper endoscopy. Patients were randomly assigned to one of three arms, with OsrhCT 4000U+ Dimethicone emulsion 4ml , with OsrhCT 8000U+ Dimethicone emulsion 4ml , and with placebo for OsrhCT+ Dimethicone emulsion 4ml. During the examination, each photograph was individually taken in 5 defined areas. The first 30 cases were collected to establish standards and method validation. The visibility score was given by the sum of the score 1-4 from 5 defined localities evaluated by a blinded endoscopist and subsequently by two or three blinded endoscopists. Other parameters monitored were examination time and a semiquantitative evaluation of residual gastric fluid.

Inclusion Criteria:

1. Patients indicated for gastroscopy examination;
2. Subjects fully understand the content, process, and possible adverse reactions of the trial and voluntary participation with signed informed consent;
3. Able to complete the research according to the requirements of the experimental plan;
4. Subjects (including their spouses) voluntarily have no pregnancy plans and use contraception during the study and within 3 months after the last administration of the study drug;
5. Aged 18-75 years (inclusive), male or female;

Exclusion Criteria:

1. Known allergy to chymotrypsin; Known to be allergic to preparation or anesthesia medication before gastroscopy examination;
2. Patients plan to undergo gastroscopic treatment, such as endoscopic titanium clip for hemostasis, esophagogastric fundal variceal ligation, endoscopic mucosal stripping, etc;
3. Subjects accessed not to stand sedation anesthesia or gastroscopy examination;
4. Severe cardiovascular, pulmonary, or cerebral diseases, such as angina, heart failure, and new-onset stroke; or severe liver disease, cirrhosis, or esophagogastric fundus varices;
5. Suspected or known esophageal fistula, tracheal fistula, intestinal obstruction, active gastrointestinal bleeding, gastric perforation, history of anatomically altered upper GI surgery;
6. Abnormal laboratory values:: alanine aminotransferase (ALT)>2 × ULN, aspartate aminotransferase (AST)>2 × ULN, serum creatinine>1.5 × ULN;
7. Female subjects who had unprotected sex within 14 days prior to screening;
8. Pregnant or breastfeeding women;
9. Subjects who have participated in any drug clinical trial and received treatment within the last 3 months;
10. Any other conditions deemed unsuitable for the study by the investigator.