Cancer-related gastrectomy can cause post-gastrectomy syndrome, which includes weight loss, dumping syndrome, and reflux esophagitis and negatively affects the quality of life. Comprehensive and individualized patient management is required; however, there is a limit to Western medicine's ability to treat these symptoms. Kampo, a traditional Japanese medicine, adapts treatments to each individual's symptoms and constitution. We treated a 68-year-old male patient with post-gastrectomy syndrome using senpukukataishasekito, a Kampo medicine. He was diagnosed with Stage II-A gastric cancer at age 66 years and underwent a laparoscopic, pylorus-preserving gastrectomy followed by chemotherapy for 13 months. He visited our clinic for chemotherapy-related fatigue, postsurgical weight loss, and limb numbness. He was prescribed both hachimijiogan and hochuekkito. At the second visit, he complained of stomach discomfort, so we prescribed senpukukataishasekito. As his stomach function improved, his body weight increased and his fatigue decreased. We suggest that senpukukataishasekito may be an effective treatment for post-gastrectomy syndrome.