Bronchoalveolar lavage has not been subjected to careful standardization. We examined the variables of lung lavage location and lavage fluid composition (pH and temperature) upon the percent of fluid recovered, cell count and differential, protein and pH in normal subjects. In the first part of the study, random order lavages of the right middle lobe (RML), right lower lobe (RLL), left lingula, and left lower lobe (LLL) were performed with 100-ml aliquots of normal saline (pH, 5.5) at room temperature (25 degrees C). Percent fluid recovery was greater in the RML and lingula than in the RLL (p less than 0.05). Cell count, cell differential, and protein were similar between lobes. In the second part of the study, each lobe was lavaged with 50-ml aliquots: the RML with normal saline at 37 degrees C, the RLL with normal saline buffered to a pH of 7.0 at 37 degrees C, the left lingula with normal saline at 25 degrees C, and the LLL with normal saline buffered to a pH of 7.0 at 25 degrees C. Percent fluid recovery was greater in the RML than in the lingula and greater in both the RML and lingula than in the lower lobes (p less than 0.05). Total cell count was significantly higher in the RML than in the LLL (p less than 0.05). Cell count per milliliter and protein recovered were not different between any lobe lavaged. The pH of recovered fluid was greater with buffered saline. Complications of fever and chills occurred in almost 50% of subjects in both parts of the study. Lavage location can affect fluid recovery. Alteration of lavage fluid composition did not affect cell or protein recovery. We suggest lavage of the RML to ensure larger fluid recovery and the highest total cell count.