The levels of specific proteins and electrolytes in stimulated whole saliva were monitored in Skylab crew members before and after each mission. With few exceptions, mission-associated compositional changes in saliva were relatively minimal. There were no changes in(formula see text), Cl-, albumin, or IgG concentrations. There were slight decreases in total protein coinciding with moderate saliva flow rate increases immediately before and after each flight. Other changes included diminutions in Na+ and lysozyme, and elevations in Mg++ and IgA. The IgA increase was the most pronounced mission-associated change observed.