Generally anti-Helicobacter pylori drugs can be taken together with anti-allergy drugs, but caution is needed if macrolide antibiotics are used to eradicate H. pylori. At present, clinical anti-Helicobacter pylori mostly use quadruple therapy, that is, a bismuth (such as bismuth potassium citrate), a proton pump inhibitor (such as omeprazole), two antibiotics (such as amoxicillin, furazolidone). Antiallergic drugs are commonly used antihistamines, often such as loratadine. Contraindications to loratadine are allergy to drug components, hepatic and renal insufficiency, pregnancy, etc. Adverse reactions are mainly dry mouth and teratogenicity. Usually there are no specific drug interactions between anti-Helicobacter pylori quartet and antihistamines, but if antihistamines and macrolide antibiotics such as clarithromycin are used together they may cause significant adverse reactions. Therefore, it is recommended to specify the type of antibiotic to be used and use or change the medication under medical supervision.