Kampo Evidence

Tim H. Tanaka, Ph.D.
Director, The Pacific Wellness Institute, Toronto, Ontario, Canada
Visiting Research Fellow, School of Health Sciences, Tsukuba University of Technology, Japan

Many Chinese herbal formulations used in the traditional Japanese medicine, Kampo are listed in the 3rd-century text Shang Ham Lun. Over the past two thousand years, the specific herbal formulations contained in this text have been handed down from generation to generation.

Although there is much anecdotal evidence, for Kampo medicine, the safety and efficacy of Kampo and Chinese medicinal practices have not been sufficiently evaluated according to modern scientific standards until recently.

In Japan where Kampo medicine is conventional practice, used by many physicians in modern hospitals and clinics, there has been strong demand for scientific evidence to defend its safety and efficacy.[1] Those calling for this testing point to the fact that stringent testing is required for the determining their safety and efficacy of herbs equilibrant to pharmaceutical drugs. Accordingly, there has been a growing number of accredited studies during the last decade that have explored Kampo medicine’s safety and efficacy.

Clinical Evidence of Kampo Formula

In 2007, the EBM Committee of Japan Society of Oriental Medicine issued the second edition of their Kampo Evidence Report. This report culled the findings of all research published on Kampo between 1999 and 2005. Of these, the EBM committee located 98 papers that they determined to be qualified. Eighty-nine of these were subjected to randomized controlled trials (RCT) and among those, 17 papers were put through double-blind studies. As yet, there has been no systematic review (meta-analysis) performed.

Below is a short summary of some of the double-blind RCT (DB-RCT) trials performed on Kampo medicine:

  • Hypertension related symptoms (flashed faces, etc.): The administration of Ourengedokuto (Huang Lian Jie Du Tang) decreased hypertension related symptoms (Muli-center study of 116 facilities)[2]
  • Upper Gastric Symptoms: Rikkunshito (Liu Jun Zi Tang) was effective in decreasing upper GI discomfort and related complaints, such as a lack of appetite.[3]
  • Irritable Bowel Syndrome: Administration of Keishikashakuyakuto (Gui Zhi Jia Shao Yao Tang) decreased abdominal pain among IBS patients. The effects were more pronounced among diarrhoea-dominant IBS cases.[4]
  • Muscle Cramping: Shakuyakukanzouto (Shao Yao Gan Cao Tang) was effective for reducing muscle cramping among cirrhosis patients.[5]
  • Obesity: 24 weeks of administering Bofutsuseisan (Fang Feng Tong Sheng San) decreased visceral fats and waist circle, as well as improved insulin resistance among obese female patients.[6]
  • Allergic Rhinitis: Shouseiryuto (Xiao Qing Long Tang) was effective in improving symptoms of allergic rhinitis.[7]

 As the double-blind study is typically considered the gold standard among drug intervention trials, the results obtained by the above DB-RCT are considered to provide strong evidence. However, one difficulty may lie in the fact that most of these studies were conducted in a single facility and some only derived their conclusions from information provided by a small number of participants. In the future, to further strengthen this evidence, it will be useful to conduct larger trials and a subsequent meta-analysis study as well.

It is important to note that the same standardized Kampo formulas were administered to the treatment groups in most of these clinical trials. When exploring the process by which we are examining Kampo, it is important to consider these scientifically sound and adequate methods as a possible liability. Kampo is an individualized treatment system based on each patient’s symptoms and constitutional patterns (sho). It is common for practitioners to administer radically different formulas to patients whom Western medicine would diagnose and prescribe for identically, if the sho of those patients are different. Conversely, the same Kampo formula may be prescribed for those patients with similar sho, even though they have different diseases. Because of this unique nature of Kampo, it is important to carefully consider an experimental design that adequately reflects clinical practice of Kampo.

A stratified randomization method according to patients’ Kampo diagnosis patterns (sho) might be useful for certain Kampo trials. However, this may be difficult to perform, since the patient’s sho may change dynamically during the trials. Kampo practitioners have long acknowledged that a patient’s sho can change very rapidly, especially under simple infectious conditions such as the common cold. One design that is thought to be useful in Kampo trials is n-of-1 RCT, which considers an individual’s unique characteristics, as well as their responses to interventions.[8] Thus far this experimental design has primarily been used in psychology but its usage has been recently expanded, seeing usage in acupuncture research trials.[9, 10]

Clinical Use of Kampo:

Scientific research has provided new and valuable information that can be used to enhance the efficacy, safety, and quality of care provided by Kampo practitioners. While this advancement is a good thing, the ancient knowledge and wisdom that Kampo represents should not be underestimated or ignored.

There is still not enough scientific data available for Kampo. Thus, the use of these techniques and prescriptions in clinical situations cannot be based solely on rigorous evidence. Just like in Western medical practices, the modern Kampo doctors will weigh the potential risks and benefits of their recommendations, while combining the current hard evidence with classical theory and experiential knowledge.

Clinical Evidence of Kampo:

[1]        Ross C. New life for old medicine. Lancet. 1993 Aug 21;342(8869):485-6.

[2]        Arakawa K, Saruta T, Abe K, Iimura O, Ishii M, Ogihara T, et al. Improvement of accessory symptoms of hypertension by TSUMURA Orengedokuto Extract, a four herbal drugs containing Kampo-Medicine Granules for ethical use: a double-blind, placebo-controlled study. Phytomedicine. 2006 Jan;13(1-2):1-10.

[3]        Harasawa S, Miyoshi A, Miwa T. Multicenter clinical trial of Rikkunshito on dysmotility-like dyspepsia using double blind between groups comparison analysis (translated from the Japanese title). Igaku no Ayumi. 1998;187(3):207-29.

[4]        Sasaki D, Uehara S, Hiwata N. Clinical efficacy of Keishikashakuyakuto on irritable bowel syndrome (translated from the Japanese title) Rinshou to Kenkyu. 1998;75:1136-52.

[5]        Kumada S, Kumada H, Yoshiba M. Double blind placebo controlled trial of shakuyakukanzouto on muscle spasms (translated from the Japanese title). Rinshou Iyaku. 1999;15(3):499-523.

[6]        Hioki C, Yoshimoto K, Yoshida T. Efficacy of bofu-tsusho-san, an oriental herbal medicine, in obese Japanese women with impaired glucose tolerance. Clinical and experimental pharmacology & physiology. 2004 Sep;31(9):614-9.

[7]        Baba S, Kousaka T, Inamura N. Efficacy of Shouseiryuto on allergic rhinitis – Double blind placebo controlled trial (translated from the Japanese title). Jibiinkouka Rinshou. 1995;88(3):389-405.

[8]        Guyatt GH, Keller JL, Jaeschke R, Rosenbloom D, Adachi JD, Newhouse MT. The n-of-1 randomized controlled trial: clinical usefulness. Our three-year experience. Annals of internal medicine. 1990 Feb 15;112(4):293-9.

[9]        Jackson A, MacPherson H, Hahn S. Acupuncture for tinnitus: a series of six n = 1 controlled trials. Complementary therapies in medicine. 2006 Mar;14(1):39-46.

[10]      Kawakita K, Shichidou T, Inoue E, Nabeta T, Kitakoji H, Aizawa S, et al. Do Japanese style acupuncture and moxibustion reduce symptoms of the common cold? Evid Based Complement Alternat Med. 2008 Dec;5(4):481-9.