It is normal to have a bitter and sour mouth after taking H. pylori medication, which may be a symptom of the adverse reaction of the medication or H. pylori infection that leads to gastric disorders. 1. Adverse reaction of drugs: the drugs used to treat H. pylori infection are mainly triple or quadruple therapy, i.e., proton pump inhibitors (such as omeprazole), bismuth (such as colloidal bismuth) plus antibiotics (such as amoxicillin), some clinical studies have found that the triple therapy may cause taste inversion after 10 consecutive days of treatment, which may result in bitter mouth and sour mouth. 2. Gastric diseases: H. pylori infection can easily lead to gastric diseases such as reflux gastritis, peptic ulcer, etc. Due to bile reflux or urease secreted by H. pylori breaks down carbon dioxide, ammonia, etc., symptoms such as bitter mouth, sour mouth, and bad taste in the mouth will occur. If oral H. pylori medication appears bitter mouth and sour mouth, it is recommended to continue to adhere to the treatment; if the symptoms are more pronounced, it is recommended to consult a doctor in a timely manner.