Pulmonary lavages were performed on 15 NZW rabbits. Ten rabbits were exposed to cotton dust extract (1g/6ml saline) endotracheally for 5 minutes and 5 rabbits were unexposed controls. Pulmonary lavages were performed 15 minutes, 1 hour or 6 hour post-exposure. Lavage fluids were centrifuged at 1000 x g for 10 minutes. Cell counts and ratios demonstrated very little recruitment at 15 minutes or 1 hour post-exposure while the 6 hour lavage demonstrated significant recruitment of polymorphonuclear leukocytes and macrophages. Lavage fluids were assayed for changes in the concentrations of prostaglandin, F(2 ), thromboxane B(2), histamine, IgG, IgM, IgA, C3, albumin, total protein and pulmonary surfactant.