ObjectiveTo observe the clinical effect of modified Jichuanjian on senile patients with slow transit constipation of spleen-kidney yang deficiency syndrome and the influence on brain-gut peptide. MethodA total of 150 senile patients with slow transit constipation were randomized into control group （75 cases） and observation group （75 cases） with the random number table method. The observation group was given modified Jichuanjian （oral， 1 dose/day， 4 weeks）， and the control group was treated with Biantong Capsules （oral， 3 capsules/time， twice/day， 4 weeks）. Data before and after treatment were recorded， including the score of major constipation symptoms， score of Patient Assessment of Constipation Quality of Life （PAC-QOL）， TCM syndrome score， spontaneous complete bowel movements （SCBM）， colonic transit test， serum 5-hydroxytryptamine （5-HT）， 5-HT 4 receptor （5-HT₄R）， somatostatin （SS）， and vasoactive intestinal peptide （VIP）， and recurrence. ResultThe total effective rate of the observation group was 93.06% （67/72）， as compared with the 74.65% （53/71） in the control group （χ²=8.974 6， P<0.01）. After treatment， the scores of major constipation symptoms， scores of four dimensions of PAC-QOL， total score of PAC-QOL， and TCM syndrome score were lower than those before treatment in the two groups （P<0.01）， and lower in the observation group than in the control group （P<0.01）. The SCBM in the observation group were more than those in the control group at the 2^nd， 3^rd， 4^th weeks after treatment （P<0.01）. The proportions of residual markers at 24， 48， 72 h after treatment were smaller than those before treatment in the two groups （P<0.01）， and smaller in the observation group than in the control group （P<0.01）. After treatment， the levels of serum 5-HT and 5-HT₄R were higher （P<0.01） and the levels of serum SS and VIP were lower （P<0.01） than those before treatment in the two groups. In addition， the levels of serum 5-HT and 5-HT₄R in the observation group were higher （P<0.01） and the levels of serum SS and VIP were lower （P<0.01） in the observation group than in the control group. The recurrence in the observation group was 29.85% （20/67） in comparison with the 58.49% （31/53） in the control group （χ²=9.932 4， P<0.01）. ConclusionModified Jichuanjian is effective for senile patients with slow transit constipation of spleen-kidney yang deficiency syndrome， which can alleviate clinical symptoms， improve quality of life， regulate the level of serum brain-gut peptide， improve the colonic transit function， increase SCBM， and reduce the recurrence.