In many pediatric infectious disease programs, ceftriaxone or cefotaxime is now the preferred drug for bacterial meningitis caused by H. influenzae, meningococci, and pneumococci. Ceftriaxone reaches a high bactericidal titer in the cerebrospinal fluid and persists at the site of infection longer than any other beta-lactam antibiotic. Short-course, once-daily therapy with ceftriaxone requires more study; currently, many pediatricians administer the agent twice daily for suspected or proven meningitis. Given the association of sequelae with prolongation of positive CSF cultures, ceftriaxone's rapid bactericidal activity is an advantage, which may require an adjunctive agent to block the inflammatory response due to antibiotic-induced release of endotoxin and other cell wall components. As empiric therapy, ceftriaxone is effective in infants and children three months to 18 years old. It is not yet recommended in neonates, because of concerns about bilirubin displacement. Thus, infants up to three months of age should receive ampicillin plus cefotaxime. In adults, ceftriaxone is effective therapy for presumed bacterial meningitis but must be combined with ampicillin initially, since L. monocytogenes meningitis cannot be excluded in most cases until CSF culture results are available.