An endoscope is easily passed through the mouth and throat and into the esophagus, allowing the doctor to view the esophagus, stomach, and upper part of the small intestine. At the end of the endoscope, a tiny light and lens enable the doctor to see if any disease is present. If necessary, the doctor will take a small biopsy of tissue for analysis. This is a quick and painless process, using specialist instruments that can be passed inside the endoscope. When the examination is finished, the endoscope is removed quickly and easily.

About 40% of people in Hong Kong are infected with Helicobacter pylori, which is very common. the risk of gastric cancer in patients with H. pylori infection is 4 to 6 times higher than non-carriers. H. pylori is a type of bacteria that can enter your body and live in your digestive tract. Over time, they can cause ulcers in the lining of your stomach or the upper part of your small intestine. H. pylori infection may also lead to stomach cancer.