Japan is the one country that did the thing everybody in this field talks about. It took a traditional herbal system, put it inside the national drug-approval process, listed the products for insurance reimbursement, and made manufacturers print approved package inserts with contraindications and incidence figures on them.
The part of this that rarely gets repeated is how it was done. Japan got there in 1874 by passing a Medical Care Law that adopted the German model of health care and stopped recognizing traditional practitioners as medical professionals. The formulas survived. The profession did not. Every Japanese physician who writes a Kampo prescription today went through an ordinary Western medical school first, and there is no separate traditional-practitioner licence to go through instead.
That is not the integration model most American advocates have in mind, and it is the one detail that cannot be transplanted.
Almost every other figure in the popular version is also narrower than it sounds. The corrections come from Japan’s own regulatory scientists, writing in peer-reviewed journals, and they are more interesting than the version they replace.
How 148 formulas got inside a national insurance system
The reinstatement was slow and bureaucratic. According to a 2012 survey paper in Evidence-Based Complementary and Alternative Medicine, the government accepted the first four Kampo formulas for insurance coverage in 1967. By 1976 the covered list had grown from four to forty-one. Today 148 Kampo extract formulas are approved for prescription use, a figure stated independently by that paper and by a 2022 review in the Journal of Natural Medicines written by a division head at Japan’s National Institute of Health Sciences.
Industrial manufacturing came first, not last. By 1957 Japanese pharmaceutical companies had worked out how to mass-produce standardized Kampo formulas as spray-dried extracts. A good manufacturing practice law for these products followed in 1987.
The governing instrument for prescription Kampo extracts is a ministry notification, number 120, issued on 31 May 1985 and titled in English as guidance on how to treat ethical Kampo extract products. The industry knows it as the Maru-Kan notification. Under it, extract products are handled as substitute products, so their approval numbers and insurance listing dates come from that substitute-product process.
Now the distinction that almost every consumer article gets wrong. The 148 is a count of distinct formulas. The Japan Kampo Medicines Manufacturers Association, drawing on the regulator’s own package-insert database as of April 2018, counted 653 separate approvals for prescription Kampo and 682 products by package insert, made by 15 manufacturers and distributed by 13 companies.
Several firms make the same formula to the same ministry standard. That is the entire point of the system, and it means both “Japan approves 148 Kampo medicines” and “Japan approves 653 Kampo formulas” are wrong.
Over-the-counter Kampo is a separate and longer list. Regulators at Japan’s Pharmaceuticals and Medical Devices Agency wrote in 2014 that an internal review standard known as the 210 over-the-counter Kampo formulae was revised in 2008 into approval standards now listing 294 formulae. The pharmacopoeia committee chair, writing in 2022, tells the same story at greater length. A project team formed in 2003, the ministry convened an expert panel on over-the-counter Kampo in 2008, the panel’s revisions went through step by step, and the new regulation was completed as ministry notification number 0830-1 on 30 August 2012. That is one process, dated by one source at its start and by the other at its finish. Both dates are correct about different things, and the article gives both.
Kampo also became a board-certifiable physician specialty in February 1998, established by the Japan Society for Oriental Medicine.
One more category exists and almost nobody outside Japan knows about it. The same agency regulators noted that Japan published an application guideline for Western traditional herbal medicines as over-the-counter drugs in 2007, and that other herbal products originating mostly in Europe could be approved as over-the-counter drugs there. Japan built a filing route for Europe’s herbal tradition before most of Europe finished building its own.
The harm record exists because Japan treats these as drugs
This section comes early for a reason. The most detailed safety information in the whole of traditional herbal medicine exists for Kampo, and it exists because a regulator required a manufacturer to publish it.
Take the approved Japanese package insert for one widely used formula, sho-saiko-to, in its tenth version of April 2014. The warnings section states the product may cause interstitial pneumonia, an inflammation and scarring of the lung tissue, which it says may result in serious outcomes such as death, and tells patients to contact a physician if they develop fever, cough or breathlessness. The insert lists three contraindications: patients on interferon treatment, patients with liver cirrhosis or liver cancer, and patients with liver dysfunction in chronic hepatitis whose platelet count is at or below 100,000 per cubic millimetre. Interstitial pneumonia is listed at an incidence of 0.1 percent, and pseudoaldosteronism at 0.1 percent. The composition lists 2.0 grams of pharmacopoeial licorice in the usual 7.5 gram daily dose.
A clinical picture sits behind those lines. A 2017 review in Respiratory Investigation searched both PubMed and the main Japanese medical abstracts database for the years 1996 to 2015 and assembled 73 patients with Japanese herbal medicine-induced pneumonitis from 59 articles, 52 of them published in Japanese. Sho-saiko-to was the most frequently implicated product at 26 percent, followed by sairei-to at 16 percent, and the authors note those products commonly contain skullcap and licorice.
The timing matters more than the rate. Sixty-five of the 73 patients, or 89 percent, developed lung inflammation within three months of starting treatment. Twenty-six patients, 36 percent, recovered simply by discontinuing the product. The rest needed immunosuppressive drugs, 13 patients were put on mechanical ventilation, and three did not survive.
The second documented harm is systemic rather than product-specific, because licorice appears across a large share of the formulas. Glycyrrhizin, licorice’s main constituent, can produce pseudoaldosteronism: swelling, low blood potassium and raised blood pressure driven by overactivity of the mineralocorticoid receptor. A 2019 study in Archives of Toxicology pooled patients from four Japanese Kampo centres between November 2011 and July 2018 and registered 97 participants, with a male to female ratio of 14 to 83.
That lopsided sex ratio is the under-reported detail. The study also found no correlation between blood pressure or swelling and the blood level of licorice metabolites, while high levels of one sulfated metabolite tracked with lower renin, aldosterone and potassium.
Which means dose alone does not predict who gets into trouble. If you are taking a licorice-containing herbal preparation and you notice new ankle swelling, unusual muscle weakness or cramping, those are reasons to get blood potassium checked promptly rather than waiting. Fever with a dry cough and breathlessness in the first three months of a new herbal product is a reason to be seen, and to bring the package with you.
The standardization claim is much narrower than you have heard
“Kampo is manufactured to pharmaceutical standards” is true and badly misunderstood. The correction comes from the man who chaired the natural medicines expert committee of the Japanese Pharmacopoeia from 2003.
The eighteenth edition of that pharmacopoeia carries monographs for 237 crude drugs, 37 Kampo extracts, 37 crude drug preparations other than Kampo extracts, nine plant oils and five essential oils. Set the 37 against the 148 approved prescription formulas and roughly 111 formulas have no pharmacopoeia monograph at all.
The author then supplies the number that rescues the claim. Those 37 listed extracts hold about 75 percent of the Kampo market, which he reads as meaning roughly 70 percent of Japan’s total herbal medicine output is standardized by the pharmacopoeia. So the honest sentence is about output, not about formulas: most of what Japan ships is pharmacopoeially standardized, while most individual formulas on the list are not.
The chronology is the bigger surprise. Before the fifteenth edition of the pharmacopoeia, Kampo extracts were not regulated by it at all. After the committee took up the project in 2003, monographs arrived in stages: 11 across the fifteenth edition and its two supplements, 17 across the sixteenth and its supplements, seven across the seventeenth, and two in the eighteenth. That adds to the 37.
This is a recent achievement built over roughly two decades, not an inheritance from antiquity. Writing that “Kampo has been standardized in the Japanese Pharmacopoeia for centuries” inverts the actual history.
The technical limits are worth knowing too. Only ten marker compounds have been prepared as pharmacopoeia reference standards for herbal medicines, because high-purity natural compounds are hard to obtain, and a usable marker has to be present at levels from 0.1 percent to a few percent. Up to the eighteenth edition, 19 reagents whose purity had been checked by quantitative nuclear magnetic resonance were listed as reference standards for the chemical assays in 37 monographs covering crude drugs and Kampo formula extracts together, which is a mixed set and not the 37 Kampo extract monographs above. Good agricultural and collection practices had been established for 68 crude drugs in Japan as of 2022. Total production of herbal medicines by Japan’s pharmaceutical industry ran to about 1.8 billion dollars in 2018, which was 2.9 percent of the country’s total pharmaceutical production value.
Pesticide residues got the same treatment, and the result is reassuring in a way only measurement can be. Researchers found that at most 31 percent of a residue on the raw crude drug migrated into a Kampo decoction, and that final residues in finished extracts ran at 10 to 14 percent of the crude drug level for freeze-dried products and 2 to 3 percent for spray-dried ones. That is the sort of number a system generates when somebody is obliged to look.
Elsewhere this library takes up what an extract label’s numbers verify. The question here is the same one asked of a pharmacopoeia instead of a label.
Nothing new has been approved since the 1980s
The closed-list quality of the system is explicit. The 2022 review states that since the 1980s no new ethical drug consisting of herbal extracts has been approved in Japan, and that even new dosage forms of existing prescription Kampo products have not been approved.
The stated reason is not safety. It is that Japan has no official guidance for the marketing authorization of a prescription natural medicine made of herbal extracts, so manufacturers do not attempt one. The author describes asking the regulator for help developing such guidance in the early 2000s and having the proposal rejected.
Some of that logjam has since moved. Bioequivalence guidance covering new dosage forms of Kampo products was published by the ministry’s evaluation and licensing division on 19 September 2021, built on research using ephedrine and pseudoephedrine as blood markers to compare a traditional decoction with the manufactured extract.
The upshot for a reader: Japan’s 148 formulas are a historical list that was closed four decades ago, not a pipeline. The regulatory achievement is real and it is about quality control of an existing inventory.
The 83.5 percent figure, and what it rests on
You will see this everywhere: more than 80 percent of Japanese doctors prescribe Kampo. The original is a single questionnaire, and the paper reporting it is unusually candid about its own design.
The survey was fielded over August and September 2008. It was sponsored by the Japan Kampo Medicine Manufacturers Association and carried out by a commercial contract research organization that the paper describes as sponsored by that same association. Invitations went to 1,800 physicians drawn at random from 17,164 doctors who had already agreed to sit on the research firm’s panel of potential respondents. A total of 684 answered, and 571 of them, or 83.5 percent, said they used Kampo in practice.
That is an industry-funded, opt-in internet panel from 2008 with a 38 percent response rate among those invited. It is still the best-documented figure available, and it is not a population estimate. Report it with that sentence attached or do not report it.
The same paper then undercuts the depth the figure implies. Overall, 41.7 percent of physicians said they used only one to four formulas, and another 30.1 percent used five to nine. Among orthopedic surgeons, 73 percent used just one to four. The leading condition treated was the common cold at 46.8 percent, followed by constipation, muscle cramp and menopausal symptoms.
Attitudes point the same way. Asked how much weight they gave the traditional pattern diagnosis called sho, 47.8 percent said they relied mainly on Western diagnosis and 36.1 percent said they considered sho in addition to it. Only 12.4 percent gave the two equal weight. Obstetrics and gynecology inverted the pattern, with 19.2 percent giving a Western diagnosis only and 57.7 percent weighing sho alongside it, which suggests the depth of use varies a great deal by specialty.
Nearly four in five physicians, 79.8 percent, said their patients took Kampo alongside Western medicine rather than instead of it. Among the 113 non-users, 44.2 percent found Kampo difficult to use and 39.8 percent said the evidence was not there. Across all 684 respondents, 62.4 percent said more clinical evidence would be needed before use increases.
Breadth with little depth, mostly for minor complaints, mostly as an add-on to a conventional diagnosis. A 2011 review in the Chinese Journal of Integrative Medicine put the prescriber share at over 80 percent and counted 345 randomized controlled trials using Kampo in Japan as of 2010, while noting that only small numbers of high-quality clinical findings can be found.
Fixed formulas, not custom prescriptions
The practical difference from Chinese herbal medicine is structural, and the regulation enforces it. A Japanese physician selects one of 148 pre-formulated, industrially extracted formulas matched to the patient’s sho. They do not compound an individual prescription from raw herbs. Kampo specialists are expected to know the full set, which is why the specialists use a far wider range than the typical prescriber.
That creates a genuine tension, and Kampo’s own advocates name it. The 2012 paper argues that randomized trials remain difficult to design because Kampo treatment is individualized to the patient’s pattern, while the same system runs on 148 fixed formulas that multiple manufacturers make to one standard. Both statements are true at once, and the gap between them is where the evidence argument lives.
The diagnostic system Kampo descends from, and the separate safety record of Chinese herbal materials, belong to this library’s article on traditional Chinese medicine.
What a reader in the United States can get
Very little of the above, and that is the honest answer.
Search the A-to-Z listing of health topics published by the federal government’s complementary health research center, as this article did in October 2026, and you will find Ayurvedic medicine and traditional Chinese medicine there. Kampo is not listed, and neither is Japanese traditional medicine under any other name. The granules do reach American buyers, through distributors whose pages carry the standard disclaimer that the statements have not been evaluated by the Food and Drug Administration and that the products are not intended to diagnose, treat, cure or prevent any disease, while restricting the clinical information to licensed practitioners.
Here is the gap, stated as a checklist of what Japan’s system supplies and a US purchase does not.
An approved indication. In Japan the product is a prescription drug listed for reimbursement. Here it is a supplement, and the disclaimer on the page says what that means.
A package insert with numbers in it. Three contraindications, a death warning and two 0.1 percent incidence figures are on the Japanese label by regulatory requirement. No equivalent document follows the product across the Pacific.
A pharmacopoeia monograph. For 37 of the 148 formulas there is one. Nothing obliges a US seller to source from a manufacturer meeting it.
A prescriber trained to the system. Japan put Kampo into the model core curriculum for medical schools from 2001 and reports that all its medical schools had adjusted their curricula by 2005. No American licensing body examines anyone on these formulas.
The European Union, by contrast, does have a registration route a Kampo product could in principle use, because its traditional-use scheme is open to systems whose tradition developed outside Europe and names Kampo among them. The United States has no comparable pathway.
What to take from Japan’s experiment
The useful lesson is not that Japan proved traditional medicine works. It is that Japan proved what happens when you measure one.
Putting these formulas under drug law produced exactly the documents a careful reader wants: contraindications, named interactions, incidence percentages, a published case series counting ventilations and deaths, and a pharmacopoeia telling you which 37 of 148 formulas have a monograph. Countries that leave the same plants in the supplement aisle produce none of that, which is why their safety record looks cleaner and is not.
If you are considering one of these products in the United States, the single most useful thing you can do is look up the Japanese package insert for that formula, which several manufacturers publish in English, and take it to the clinician who manages your other prescriptions. The interferon contraindication and the licorice problem are the kind of detail a pharmacist can act on and a product label here will not tell you.
Sources
- Goda Y.. “Regulatory science of natural products. Journal of Natural Medicines, 2022;76(4):732-747. PubMed. DOI: 10.1007/s11418-022-01639-w (full text read via PubMed Central: 37 of 148 formulas with a Japanese Pharmacopoeia monograph; 75% market share and roughly 70% of output; monograph counts by edition; no new ethical herbal extract drug since the 1980s).” pubmed.ncbi.nlm.nih.gov
- Moschik EC, Mercado C, Yoshino T, Matsuura K, Watanabe K.. “Usage and Attitudes of Physicians in Japan Concerning Traditional Japanese Medicine (Kampo Medicine). Evidence-Based Complementary and Alternative Medicine, 2012. PubMed. DOI: 10.1155/2012/139818 (full text read: survey funding and panel design, 83.5% of 684 respondents, formula-breadth and sho figures, 1874 Medical Care Law, 1967 and 1976 coverage).” pubmed.ncbi.nlm.nih.gov
- Maegawa H, Nakamura T, Saito K. (Office of OTC/Generic Drugs, Pharmaceuticals and Medical Devices Agency, Japan). “Regulation of traditional herbal medicinal products in Japan. Journal of Ethnopharmacology, 2014;158 Pt B:511-5. PubMed. DOI: 10.1016/j.jep.2014.07.012 (210 OTC Kampo formulae revised in 2008 to standards listing 294; 2007 application guideline for Western traditional herbal medicines as OTC drugs).” pubmed.ncbi.nlm.nih.gov
- Enomoto Y, Nakamura Y, Enomoto N, Fujisawa T, Inui N, Suda T.. “Japanese herbal medicine-induced pneumonitis: A review of 73 patients. Respiratory Investigation, 2017;55(2):138-144. PubMed. DOI: 10.1016/j.resinv.2016.11.007.” pubmed.ncbi.nlm.nih.gov
- Takahashi K, Yoshino T, Maki Y, et al.. “Identification of glycyrrhizin metabolites in humans and of a potential biomarker of liquorice-induced pseudoaldosteronism: a multi-centre cross-sectional study. Archives of Toxicology, 2019;93(11):3111-3119. PubMed. DOI: 10.1007/s00204-019-02588-2.” pubmed.ncbi.nlm.nih.gov
- Motoo Y, Seki T, Tsutani K.. “Traditional Japanese medicine, Kampo: its history and current status. Chinese Journal of Integrative Medicine, 2011;17(2):85-7. PubMed. DOI: 10.1007/s11655-011-0653-y.” pubmed.ncbi.nlm.nih.gov
- Tsumura & Co.. “TSUMURA Shosaikoto Extract Granules for Ethical Use (TJ-9), approved Japanese package insert, 10th version, revised April 2014 (warnings on interstitial pneumonia; three contraindications; interstitial pneumonia and pseudoaldosteronism each listed at 0.1%; 2.0 g Glycyrrhiza per 7.5 g daily dose).” tsumura.co.jp
- Japan Kampo Medicines Manufacturers Association. “Kampo Formulations for Prescription: Information in Package Inserts, introduction, version 2.1 dated 22 March 2019 (Ministry of Health and Welfare Notification 120 of 31 May 1985; 653 approved formulations and 682 products from 15 manufacturers and 13 distributors, from the regulator's package-insert database as of 9 April 2018).”
- National Center for Complementary and Integrative Health, National Institutes of Health. “Health Topics A-Z (checked October 2026: no entry for Kampo or Japanese traditional medicine; entries exist for Ayurvedic Medicine and Traditional Chinese Medicine).” nccih.nih.gov
- European Medicines Agency, Committee on Herbal Medicinal Products. “Questions and Answers on the European Union framework for (traditional) herbal medicinal products, including those from a non-European tradition, EMA/HMPC/402684/2013 Rev. 1, 22 November 2023 (Kampo named among the non-European traditions whose products may qualify).” ema.europa.eu
- TCMzone LLC (US distributor). “Honso Kampo overview page: cited only as the distributor's own marketing, for the disclaimer language that the statements have not been evaluated by the Food and Drug Administration and the restriction of the clinical information to licensed practitioners.” tcmzone.com