A solitary pyogenic liver abscess usually requires open surgical drainage. Digital exploration of the cavity is important for eliminating any loculations and avoiding complications after the drainage procedure. Chronic liver abscesses which are enclosed by a fibrous capsule and thus may simulate a neoplastic tumor are best treated by atypical liver resection close to the abscess or by a procedure similar to pericystectomy. Early radical operation is indicated for a complicated liver abscess whenever two drainage procedures have failed and the patient's condition is deteriorating. In such a case the development of sepsis and (or) multiple abscesses caused by an internal fistula to the bile duct system are a potential and increasing danger. Anatomical liver resection, though the most radical operation, carries a comparatively low risk as its mortality rate is less than 10%. The prognosis of solitary abscess has improved during the last decade due to an earlier diagnosis and adequate surgical drainage in combination with antibiotics. Anaerobic liver abscesses have the best prognosis.