The pathologic sequela of reduced neutrophil function have been reviewed. In each case, the mechanism for the reduction in function has been elaborated when known. Special emphasis has been placed upon the pathologic changes in the oral cavity as a result of neutrophil dysfunction. Numerous examples have been given, and the overriding conclusion must be that any impairment of neutrophil function will lead to some degree of increased susceptibility to infection. Perhaps the tissue most sensitive to pathologic changes in the oral cavity is the periodontium. In cases of severe neutrophil dysfunction there is severe periodontal breakdown. But also in cases of "mild" neutrophil dysfunction, where there is no other infection, such as in individuals with LJP, there is severe periodontal breakdown. The molecular basis of neutrophil dysfunction is beginning to be understood in individuals with LJP. It is our hope that further research in this area will help to delineate the pathogenesis of periodontal diseases.