Taking norfloxacin is not a good way to check for H. pylori, which can be a false negative. Helicobacter pylori is a bacterial infection associated with the development of gastrointestinal diseases, and the main screening method is the breath test. If you have taken drugs that inhibit gastric acid or antibiotic drugs such as omeprazole, levofloxacin, cephalosporins, etc. before the test, the activity of H. pylori will be reduced, and there will be false negatives when the test is performed. Norfloxacin is an antibiotic drug and can affect the test results. Check Helicobacter pylori should pay attention to stop using antibiotics such as levofloxacin and bismuth pectin and other bismuth agents 4 weeks before the examination, and stop using acid-suppressing drugs such as omeprazole 2 weeks before the examination, in addition to needing to fasting before the examination, and if you have carried out Helicobacter pylori treatment before, you need to stop the drug and go to the hospital for review again after one month, so that the results of the examination will be more accurate. Helicobacter pylori is contagious and can be transmitted through unclean food and unclean utensils, etc. You should pay attention to the cleanliness of your diet to avoid infecting other people.