Health certificate is only required for people engaged in public service industry, and its purpose is to prevent some infectious diseases from spreading to the masses in public service. Therefore, the key point of health certificate physical examination is to see if you have any infectious diseases that are not allowed by laws and regulations, but it does not mean that you are healthy.
For example, the stomach disease and gastric perforation you mentioned are really unhealthy, but such diseases will not cause infection. In this case, you can apply for a health certificate.
The situation that the health certificate cannot be obtained mainly includes:
Salmonella, Shigella, tuberculosis, hepatitis A, hepatitis E, onychomycosis, etc.
If it is unqualified, a review will generally be arranged.