The possibility that pesticides are secreted in the saliva and that this secretion can be used to assess exposure to pesticides is discussed. Both Kepone and carbaryl were tested through a series of in vitro studies and in vivo experiments including both acute and subchronic studies. In the in vivo studies, both Kepone and carbaryl were detected in the saliva in the first twenty-four hours, but seldom thereafter. Analysis of urinary samples indicated a rapid clearance of the substances from the animals. In vitro uptake and efflux studies suggested that movement of both substances was by passive diffusion and reached a plateau after 60 minutes of incubation. Efflux rates were unaffected by experimental conditions, but were ten times faster for carbaryl.