To investigate the effect of Zijinlong Tablets（紫金龙片）combined with intravenous immunoglobulin in the treatment of lower respiratory tract infection in the elderly.

Totally 302 elderly patients with lower respiratory tract infections admitted to the hospital from March 2021 to March 2023 were selected and randomly grouped，each with 151 cases.Based on conventional treatment，the control group was given intravenous immunoglobulin，and the study group received Zijinlong Tablets combined with intravenous immunoglobulin.Then the clinicalefficacy，ratio of forced expiratory volume in the firstsecond to forced vital capacity（FEV₁/FVC），peak expiratory flow（PEF），maximum voluntary ventilation（MVV），arterial partial pressure of oxygen（PaO₂），arterial partial pressure of carbon dioxide（PaCO₂），interleukin-6（IL-6），C-reactive protein（CRP），interleukin-1（IL-1），procalcitonin（PCT），immunoglobulin-（Ig）A，IgG，IgM and T-lymphocyte subsets（CD3⁺，CD4⁺，CD8⁺）were compared.

The study group reported a higher overall efficacy rate than the control group（93.38% vs85.43%，P<0.05）.An increase in PEF，MVV and FEV₁/FVC were observed in all patients after treatment，and the increase was more notable in the study group than those in the controlgroup（P<0.05）.An elevation in PaO₂ and a decrease PaCO₂ were detected in all patients，and both improvements were more remarkable in the study group than those in the control group（P<0.05）.After treatment，the levels of IL-6，CRP，IL-1 and PCT showed a decrease in all patients，and the three parameters were all lower in the study group than those in the control group（P<0.05）.The levels of IgA，IgG and IgM demonstrated an increase in all patients，and were all larger in the study group than those in the control group（P<0.05）.An elevation in CD3⁺and CD4⁺and a decrease CD8⁺were found in all patients，and both improvements were more obvious in the study group than those in the control group（P<0.05）.

The application of Zijinlong Tablets combined with intravenous immunoglobulin in the treatment of lower respiratory tract infection in the elderly can effectively improve the pulmonary function and arterial blood gas indexes，attenuate the cellular inflammatory response，ameliorate the body immune function and promote the recovery of the patients.