Objective:To investigate the effect of probiotic adjuvant therapy on efficacy and immune function in elderly patients with heart failure(HF).Methods:103 elderly HF patients was selected and divided into a combination group(n=52)and a control group(n=51)according to different treatment methods.The control group received standard HF therapy,whereas the combination group received adjunctive oral probiotic adjuvant on the basis of the control group.Following 3 months of continuous intervention,param-eters including cardiac function,immunological profiles,nutritional status,exercise tolerance,and quality of life were compared between the groups.Results:After treatment,the ratio of early to late diastolic mitral inflow peak velocities(E/A)and left ventricular ejection fraction(LVEF)in both groups were higher than those of before treatment(P<0.05),and the combination group was higher than the control group(P<0.05).The left ventricular end-systolic diameter(LVESD),N-terminal pro-brain natriuretic peptide(NT-proBNP)levels in both groups decreased(P<0.05),and the combination group was lower than the control group(P<0.05).Immunoglobulin G(IgG),IgA,IgM levels,and Mini Nutritional Assessment-Short Form(MNA-SF)scores in both groups were higher than those of be-fore treatment(P<0.05),the combination group was higher than the control group(P<0.05).The 6-minute walk test(6MWT)dis-tance in both groups was greater than that of before treatment(P<0.05),with the combination group showed a longer distance than the control group(P<0.05).The Minnesota Living with Heart Failure Questionnaire(MLHFQ)scores in both groups were lower than be-fore treatment(P<0.05),with the combination group showed lower scores than the control group(P<0.05).Conclusion:Probiotic adjuvant therapy effectively improves cardiac function,immune status,and nutritional parameters in elderly HF patients.Additionally,this combined regimen demonstrates positive clinical significance in enhancing exercise capacity and quality of life in HF patients.