Objective: To study the relationshia between PGE 2 in gingival tissue and subgigival veillonella species from patients with periodntitis.Methods:The levels of PGE 2 were determined by radio immunoassay and the levels of Veillonella species were detected by anaerobic culture methods.Results:The quantities of PGE 2 in gym tissue with periodontitis were obviously higher than those of normal people and positive correlation with the quantities of subgingival Veillonella.Conclusion:The quantities of PGE 2 had a lose relationship with the destruction of alveolar bone Veillonella had an important role in periodontitis.