Objective To analyse effect of dexamethasone combined with cefminox perioral injection on serum immunoglobulin in patients with oral and maxillofacial infection.Methods 46 patients who were diagnosed with oral and maxillofacial infection in our hospital were collected.All patients were randomly divided into experimental group and control group,23 cases in each group.Control group was treated with cefminox 3.0 g,one time per day perioral injection on the basis of control group treatment, experimental group were given dexamethasone sodium phosphate injection 10 mg, one time per day perioral injection, After the treatment, the serum levels of immunoglobulin IgA,IgG,IgM,CRP and routine blood test were detected in all patients.Results Compared with control group post-treatment, the serum levels of IgA,IgG and IgM were lower in experimental group (P<0.05);the serum level of CRP was lower in experimental group (P<0.05);the serum levels of WBC,NET% were lower in experimental group (P<0.05). Conclusion The dexamethasone combined with cefminox perioral injection can significantly reduce the serum level of immunoglobulin,CRP,WBC and NET% in patients with oral and maxillofacial infection,control the infection and inhibit the development of the disease.