Acute bronchitis is an acute cough illness in otherwise healthy adults that usually lasts 1 to 3 weeks. This review describes the pathophysiology of the condition and provides a practical approach to the evaluation and treatment of adults with uncomplicated acute bronchitis. Practical points to be made are:1. Respiratory viruses appear to cause the large majority of cases of uncomplicated acute bronchitis.2. Pertussis infection is present in up to 10% to 20% of adults with cough illness of more than 2 to 3 weeks' duration. No clinical features distinguish pertussis from nonpertussis infection in adults who were immunized against pertussis as children.3. Transient bronchial hyperresponsiveness appears to be the predominant mechanism of the bothersome cough of acute bronchitis.4. Ruling out pneumonia is the primary objective in evaluating adults with acute cough illness in whom comorbid conditions and occult asthma are absent or unlikely. In the absence of abnormalities in vital signs (heart rate > 100 beats/min, respiratory rate > 24 breaths/min, and oral body temperature > 38 degrees C), the likelihood of pneumonia is very low.5. Randomized, placebo-controlled trials do not support routine antibiotic treatment of uncomplicated acute bronchitis.6. Randomized, placebo-controlled trials have shown that inhaled albuterol decreases the duration of cough in adults with uncomplicated acute bronchitis.7. Intervention studies suggest that antibiotic treatment of acute bronchitis can be reduced by using a combination of patient and physician education. Decreased rates of antibiotic treatment are not associated with increased utilization, return visits, or dissatisfaction with care.