One-hundred and seventy-one cases of pertussis were observed at the Institute of Infections Diseases and at the 2nd Division of Infectious Diseases of the Policlinico Umberto I in Rome from January 1, 1987 to June 30, 1991. All subjects were treated according to a therapeutic protocol consisting of macrolides (erythromycin or myocamicin) at doses of 40-50 mg/die, betamethasone 0.1 mg/kg/die, specific immunoglobulin G at doses of 0.5 ml/kg repeated after 24 hours (new born babies and babies still unweaned) and oxygen therapy during the paroxystic fits. In 20 patients who were over the first year of life and who had serious asphyxiated fits, bronchodilators (trimetochinol or salbutamol) were added to the previous therapeutic scheme. Our data show both efficacy of therapeutic protocol and importance of early starting the treatment to shorten the length of disease, the strength of asphyxiated fits, and the risk of contagion.