This study compared the systemic absorption of topically administered lidocaine in elderly and young adult patients who were undergoing fiberoptic bronchoscopy. Fourteen elderly subjects aged 60-72 years (mean 67 years) and five young subjects age 31-48 years (mean 42 years) were compared with respect to dosage requirements to achieve satisfactory local anesthesia, rate and extent of lidocaine systemic absorption, plasma drug levels, elimination half-life, and drug side effects. Blood samples were drawn prior to, during, and for an average of 3 hours after the completion of bronchoscopy. Lidocaine plasma concentrations averaged in the range of 3.04-0.88 micrograms/ml from the beginning of the procedure to the end of blood sampling. Despite high cumulative amounts of 19 mg/kg (1200 mg) of lidocaine administered topically, the regimen proved relatively safe and achieved satisfactory anesthesia. In patients without known risk factors either for delayed hepatic lidocaine clearance or for enhanced mucosal absorption, the regimen is suitable for both young and old individuals.