The liver is involved in systemic infections and also (due to the fact that it lies at the distal end of the portal circulation) many others that involve the gastrointestinal tract. Systemic bacterial infections are often accompanied by hepatocellular dysfunction; the pathogenesis of this event is poorly understood. Opportunistic infections are increasingly encountered in advanced human immunodeficiency virus disease. Granulomatous involvement of the liver occurs in a wide range of infections (and also malignancies). Pyogenic liver abscess still carries a significant mortality rate, although there is overall evidence that management is improving. In a tropical context, invasive hepatic amebiasis remains the most common cause of a space-occupying hepatic lesion or lesions. Schistosomal liver disease, complicated by portal hypertension, is a major gastroenterologic problem in Africa, the Middle East, and southern America, and biliary parasitic infections (with resultant adenocarcinoma) cause severe morbidity and mortality in southeastern Asia.