Lung abscess is a collection of pus within the lungs caused by aspiration or infection, usually by anaerobic bacteria. Risk factors include periodontal disease, impaired swallowing, and conditions causing altered consciousness. Symptoms include cough with purulent sputum and chest pain. Diagnosis involves chest x-ray, bronchoscopy, and culture of sputum. Treatment is long-term IV and oral antibiotics, postural drainage, and surgery if antibiotics fail or cause massive hemoptysis. Prevention involves good oral hygiene and care to prevent aspiration during unconsciousness or seizures.