The most common problems in the management of serious bacterial infections were reviewed. As illustrations, the diagnostic and therapeutic strategies in two types of deep-seated infections--both associated with a poor penetration of antibiotics--were discussed: (1) In suppurative central venous thrombophlebitis, conservative therapy frequently fails; if so, one should promptly switch to a surgical approach; (2) in most patients with a parapharyngeal space infection, a non-surgical approach can be recommended including early diagnosis by computed tomography (CT), CT-guided needle aspiration, prompt administration of benzylpenicillin in high and frequent dosages or continuously, and follow-up by CT. This regimen may prevent radical surgery even in the presence of deep neck or mediastinal abscesses.