Urea breath test is simple, fast, and effective in detecting Helicobacter pylori. It is suitable for post-medicine re-examination or asymptomatic examination. First, blow in the air bag, and then take the test pill. After 30 minutes, blow in another air bag, and the results will be available after 3 working days. Helicobacter pylori can infect the stomach, pain or discomfort in the upper abdomen, nausea or vomiting. The International Agency for Research on Cancer has also designated Helicobacter pylori as the first type of carcinogen, which can cause stomach cancer. Helicobacter pylori infection is the most common chronic bacterial infection in the world, and 40 % people in Hong Kong are infected with Helicobacter pylori. Helicobacter pylori is most commonly spread through saliva and vomiting. It is also easily spread through contamination of food, water, and excreta. Many people get infected in childhood.