Suitable antimicrobials given during the catarrhal stage of whooping cough can attenuate the course of the disease. The efficacy of antibiotics administered prophylactically during the incubation period remains controversial but appears to be beneficial. Currently, erythromycin given for two weeks is the antibiotic of choice for pertussis. No treatment failures were observed with erythromycin estolate. Erythromycin ethylsuccinate and stearate must be given at high dosages (50-60 mg/kg/day) in order to achieve sufficient concentrations in the respiratory secretions. With ampicillin and amoxicillin treatment failures have been observed. The role of josamycin and co-trimoxazole in pertussis remains open.