Status of urological Kampo medicine: a narrative review and future vision

Clinical evidence for traditional Japanese Kampo medicine has been provided by modern scientific methodologies. Indeed, more than 150 Kampo formulations have been approved for use as prescription drugs by the Ministry of Health, Labor and Welfare of Japan, and are widely used in daily medical practice. More than 10 of these formulations can be used for urological problems, especially in cases of lower urinary tract dysfunction. However, there are few opportunities to introduce urological Kampo medicines for worldwide use, and the status of urological Kampo medicine has not been reviewed yet. Here, we present a narrative review to introduce the current status of urological Kampo medicine in Japan. First, we introduce the essence of general Kampo medicine, including its history and current status in Japan. We focused of Sou-Sei-Sou-Koku, "promotion and inhibition network among the Five Elements," which is the central dogma of Kampo medicine. To present Kampo medicine as scientific medicine, neural cross-talk among pelvic organs is presented in comparison with Sou-Sei-Sou-Koku. Second, we list representative urological Kampo formulations used for lower urinary tract symptoms. Furthermore, we also discuss their roles in the urological field, including their position in Japanese clinical guidelines. Third, we propose the multi-organ targeting strategy using Kampo formulations as a future vision. Dai-Ken-Chu-Tou (a common Kampo formulation for gastrointestinal problems and hypersensitivity to cold) is one candidate, and we present the results of a preliminary study using this Kampo medicine formulation.