To observe the clinical effects of compound cantharides Capsule on Th17 / Treg cell imbalance in gastric cancer and quality of life.Methods:A total of 60 cases of gastric cancer selected in Qingdao Cancer Hospital from September 2015 to August 2017 were observed and divided into control group and observation group,with 30 cases in each group.The control group received chemotherapy with FOLFOX4 regimen,and 14 d as a treatment course for 4 cycles.The observation group was additionally treated with Fufang Banmao Capsules,0.75 g / time,2 times / day.The 2 groups were treated with 21 d as a treatment cycle for 2 cycles.After treatment,serum tumor markers CEA,CA19-9,CA242 and CA72-4 levels,quality of life score(SF-36),toxic and side effects,survival rate,percentage of Th17 cells in peripheral blood,percentage of Treg cells and Th17 / Treg ratio in 2 groups were compared.Results:1)Peripheral blood CA19-9,CEA,CA72-4 and CA242 decreased after treatment in 2 groups.Compared with control group,the observation group decreased significantly(P<0.05); 2)Body,role,emotional,social and overall quality of life scores in 2 groups were higher than that before treatment.The observation group was better than control group(P<0.05); 3)The major adverse reactions of 2 groups were myelosuppression and gastrointestinal symptoms.Occurrence difference of bone marrow suppression in 2 groups had no statistical differences(P>0.05).The incidence rate of gastrointestinal symptoms in observation group was lower than that of the control group(P<0.05).4）Peripheral blood Th17 cells than,the percentage of Treg cells and Th17 / Treg decreased in 2 groups.The observation group decreased more significantly than control group(P<0.05).The differences were statistically significant(P<0.05).Conclusion:There is a significant immune escape phenomenon in gastric cancer.Fufang Banmao capsules can improve the curative effects of gastric cancer by correcting the imbalance of Th17 / Treg cells and quality of life of patients.