Lung abscesses are cavitating lesions containing necrotic debris caused by microbial infection. Patients with chronic lung disease, bronchial obstruction secondary to cancer, a history of aspiration or risk of aspiration caused by alcoholism, altered mental status, structural or physiologic alterations of the pharynx and esophagus, neuromuscular disorders, anesthesia, are among others at higher risk of developing lung abcess. The main bacteriological characteristics, the diagnosis, therapy and prognosis are considered. The problem of antimicrobial resistance is also referred.