Symptoms of H. pylori infection include acid reflux, nausea and vomiting, severe bad breath and epigastric pain. 1. Acid reflux, nausea and vomiting: H. pylori usually induces a large amount of gastrin secretion, leading to excessive stomach acid, and patients usually show symptoms such as acid reflux and heartburn, nausea and vomiting. 2. Severe bad breath: After being infected with Helicobacter pylori, patients usually have the symptom of heavy breath and often have a peculiar oral odor. 3. Epigastric pain: After being infected with H. pylori, patients may experience epigastric bloating, discomfort or pain after eating, and may be accompanied by other adverse symptoms such as hiccups, bloating and loss of appetite. Patients who experience these symptoms are advised to seek prompt medical attention to avoid delays.