The authors performed investigations in Phosphoric Fertilizers Works in Gdansk to find out whether or not the work environment contaminated by fluorine compounds affects the activity of lysozome--the protective enzyme of saliva. In some in vitro experiments lysozome activity in exposed workers' saliva was found to be significantly lowered, as opposed to that in unexposed workers. In vivo experiments did not indicate any effects of work conditions on the activity of this enzyme. The obtained results, in vivo and in vitro, do not demonstrate any clear effects of work environment in the Phosphoric Fertilizers Works in Gdansk, upon lysozome activity in workers' saliva.