This guide is a summary of the report by the French High Council for Public Health on how to respond to one or more cases of whooping cough, which was approved on January 16, 2004. The report details epidemiological and clinical data, biological diagnosis, treatment of the disease, and methods of prevention. The report and its accompanying bibliography are available on the website of the Directorate General for Health. Pertussis is a bacterial infection of the lower respiratory tract that is typically accompanied by little or no fever, has a prolonged course, and is highly contagious. Since vaccination coverage has been high, this disease primarily affects infants too young to be vaccinated, as well as adolescents and adults who have lost the protection conferred by the vaccine (< 10 years) or the disease (< 15 years). The incubation period is 10 days (range: 7 to 21 days), and the disease remains contagious for up to 3 weeks after the onset of symptoms if no antibiotic treatment is administered. (R.A.)