To observe the therapeutic effects of compound cantharidin capsules combined with pemetrexed+cisplatin chemotherapy on the patients with advanced lung adenocarcinoma.Methods:A total of 80 patients with advanced lung adenocarcinoma admitted to Deyu Medical Ma'anshan General Hospital from January 2017 to December 2021 were enrolled and randomized into an observation group(n=40) and a control group(n=40).The control group received pemetrexed+cisplatin as first-line chemotherapy，and the observation group was additionally administrated with compound cantharidin capsules.The short-term therapeutic effect，levels of tumor markers，immune functions，adverse reactions，and progression-free survival(PFS) were compared between the two groups.Results:The objective response rate(ORR) and disease control rate(DCR) in the observation group were higher than those in the control group(P<0.05).After treatment，the observation group showed lower levels of carcinoembryonic antigen(CEA)，tissue polypeptide-specific antigen(TPS)，and carbohydrate antigen 153(CA153) and higher CD3+，CD4+，and CD4+/CD8+ levels than the control group(P<0.05).In addition，the observation group had lower incidence of thrombocytopenia，leukopenia，gastrointestinal reactions，and myelosuppression and longer median PFS than the control group(P<0.05).Conclusion:Compound cantharidin capsules can improve short-term curative effect in the patients with advanced lung adenocarcinoma treated with pemetrexed+cisplatin，lower the levels of tumor markers，improve immune function，and reduce adverse reactions.