Anaerobes are the predominant components of oropharyngeal mucous membranes bacterial flora, and are therefore a common cause of bacterial infections of endogenous origin of upper respiratory tract and head and neck in children. This review summarizes the aerobic and anaerobic microbiology and antimicrobial therapy of acute and chronic upper respiratory tract infection and other head and neck infections. These infections include acute and chronic otitis media, mastoiditis and sinusitis, pharyngo-tonsillitis, peritonsillar, retropharyngeal and parapharyngeal abscesses, suppurative thyroiditis, cervical lymphadenitis, parotitis, siliadenitis, and deep neck infections including Lemierre syndrome. The recovery from these infections depends on prompt and proper medical and when indicated also surgical management.