Fasting is required before the H. pylori blow test and it needs to be done for at least 3 hours so that the results will not be affected due to the effect of food. H. pylori is a gram-negative bacillus that can survive and multiply in the acidic environment of the stomach, and infection can lead to gastritis, peptic ulcers, and long-term progression may lead to gastric cancer, so H. pylori is classified as a class I carcinogen. H. pylori blow test generally refers to the carbon 14 and carbon 13 (C-14/C-13) breath test, which generally requires fasting for 3 hours and more before the test, and urea capsules need to be taken with warm water before the test, and the exhaled gas is checked half an hour later. If the test is not done on an empty stomach, the ingredients in the food may affect the accuracy of the test results. It is recommended to go to the regular hospital for C-14/C-13 breath test, and take treatment if necessary according to the test results.