Parapneumonic effusion is a common clinical problem, and those that go on to develop pleural infection have high morbidity and mortality. The process of pleural infection evolution involves changes in pleural physiology that are increasingly being elucidated and understood. The microbiology of pleural infection has changed over recent years, with clear differences emerging between hospital- and community-acquired infections. Using biochemical surrogates of infection, chest drainage can be undertaken rationally for those who do not respond to antibiotics alone. Recent data suggest that fibrinolytics do not influence outcomes in pleural infection. The optimal type and timing of surgery remain controversial.