A 19-year-old man was referred to our clinic for frequent nausea and vomiting. At age 16, he started to have periodic bouts of nausea and vomiting. During an attack, he would experience vomiting more than ten times a day and was unable to eat, which resulted in hospitalization for a week. Inpatient investigations did not reveal any abnormalities except dehydration. Between attacks, he was asymptomatic. Initially, he had attacks a few times a year. However, beginning at age 19, the attacks occurred almost every month. At our clinic, routine physical examination and laboratory tests were unremarkable. On Kampo medical examination, he had qi stagnation and qi counter-flow. He was diagnosed with cyclic vomiting syndrome. Hangekobokuto was administered with improvement of his symptoms. Hangekobokuto may be effective for cyclic vomiting syndrome with qi stagnation and qi counter-flow as diagnosed with Kampo medicine. This suggests the effectiveness of Kampo medicine in functional gastrointestinal disorders.