Antimicrobial resistance occurs when disease-causing microorganisms no longer respond to medicines designed to treat them. Misuse and overuse of antimicrobials contribute to resistance and can make infections more difficult to treat. Medicine choices should be discussed with an appropriately qualified healthcare professional. This article does not recommend an antibiotic, dose or treatment duration. Microorganisms become resistant, not the patient’s body. Unnecessary antibiotic use can make infections harder to treat in the community. For any medicine, ask what it is for, how to use it, what interactions matter and what to do about missed doses or side effects. Do not share medicines or assume an old prescription suits a new illness. Ask a pharmacist or prescriber.