Objectives: The purpose of this study was to investigate whether the symptoms of fecal incontinence (FI) or anal sphincter dysfunction are improved by daikenchuto (DKT). Methods: This is a retrospective observational study that analyzes the effects of DKT. The study was conducted at Kunimoto Hospital. Patients who visited the hospital from January 2012 to December 2016 due to symptoms of FI with a certain degree of chronic constipation and who took DKT were enrolled. The drug to be evaluated was "Tsumura Daikenchuto Extract Granules for Ethical Use (TJ-100) " manufactured by Tsumura & Co., Tokyo, Japan. The primary outcome measures were changes in the scores of the Cleveland Clinic Incontinence Score (CCIS) and Constipation Scoring System (CSS) before and after the administration of DKT. Results: A total of 157 patients were enrolled. On the CCIS, "leakage of solid stool," "leakage of liquid stool," "pad use," and "total score" were significantly improved. On the contrary, on the CSS, the score of "type of assistance" was significantly improved after the administration of DKT, but no significant difference was found in the total score. On the Bristol Stool Form Scale, the administration of DKT showed a tendency to normalize stool consistency. Maximum resting anal pressure and maximum squeeze anal pressure significantly increased after the administration of DKT. No side effects caused by DKT were observed during the study. Conclusions: DKT appears to be a safe and useful agent for the management of FI in patients with defecation disorders and internal anal sphincter dysfunction.