Researchers over the past 40 years have utilized bronchoalveolar lavage (BAL) as a tool to help expand our knowledge of pulmonary medicine. Many reports have documented BAL as a safe procedure for research subjects. New technologies, such as flow cytometry, have provided much needed insight into the mechanisms behind several pulmonary diseases. The concept of the lung as an easily accessible mucosal site to monitor local immune responses and treatment effects is evolving. Future BAL research with human subjects, aided by new technology, will undoubtedly yield clinically relevant information regarding biomarkers of disease and new therapeutic targets.