A 56-year-old male presented with fulminant subdural empyema manifesting as rhinorrhea, periorbital cellulitis, fever, convulsions, and consciousness disturbance. Neuroimaging showed pansinusitis with skull destruction and extensive subdural empyema. Decompressive craniectomy, irrigation of the empyema, and subdural drainage were performed. Endoscopic sinus surgery was performed to remove the source of infection at the same time. Streptococcus milleri was cultured from the pus. Continuous irrigation of the subdural space with saline containing gentamicin for 7 days resulted in prompt elimination of pus and debris. The patient was discharged with only a slight neurological deficit.