Respiratory tract symptoms are one of the major reasons for consultations with general practitioners. Most patients present because of symptoms that distress them or their family, or for reassurance that the symptoms do not represent something serious, or in order to receive medication. Many patients believe that their symptoms are due to an infection and expect to receive an antibiotic. These expectations influence the doctor's prescribing such that many patients will receive antibiotics even if the general practitioner considers these not to be required. This article describes the principles of rational antibiotic prescribing for lower respiratory tract infections in primary care, including disorders such as acute bronchitis, acute exacerbations of chronic obstructive pulmonary disease (COPD) and community-acquired pneumonia.