Kampo physicians were appalled by the sudden cut-off of the traditional medical system in 1875. Several of them organized the Onchi-sha Association to defend and preserve Kampo. The principal figures involved were Gyoko Yamada, Shohaku Asada, and Risshi Mori. Beginning in the 1880s they recruited several other Kampo physicians and set up some small hospitals emphasizing Kampo practices. However, by 1887, the organization was disbanded after key members either left the organization due to internal policy dissent or died of old age. In 1895, an attempt to get legislative reform of the medical licensing regulations to allow separate licensing in Kampo failed. Kokkan Azai, one of the main activists in this reform effort died in 1902, with Kampo virtually stamped out.

Despite the highly successful efforts of the Meiji government to eliminate Kampo, a few Kampo physicians remained who continued to promote their tradition as the Meiji gave way to the subsequent Taisho government. Although the Taisho still retained its devotion to Western medicine, some revival became possible after 1902, since Kampo was no longer seen as a potential threat to modernization and there was no need to make it a specific target of suppression. The Kampo physicians wrote about the value of Kampo; for example, Keijuro Wada wrote Ikai-no-tettsui (The Iron Hammer of the Medical World) in 1910 and Tadanao Nakayama wrote Kampo-igaku-no-shin-kenkyu (New Study of Kampo Medicine) in 1927. In addition, a course on Kampo medicine was set up at Takushoku University in 1937 (such a course is currently taught at Toyama Medical and Pharmaceutical University).

After the 1920s, Kampo was promoted not by old doctors from the pre-Meiji era, but by enthusiastic converts from the modern medical profession. Keisetsu Otsuka, who became one of the most famous Kampo practitioners of the 20th Century, told his story of conversion from Western medicine to Kampo.

In 1920, I was a second-year student at Kumamoto Medical School [a Western medicine school]. One day while walking through a park in the suburb of Kumamoto, I saw a sign that said: Chinese Medicine Hospital. I have seen many hospital signs before and since, but have forgotten them all. Only this one can I still picture in my mind's eye. When I looked at the words "Chinese Medicine," I remember feeling only contempt. I didn't know at the time that the hospital dated from the Tokugawa era and was most famous for its Chinese herbal medicine. I thought the sign was merely advertising for an unlicensed practitioner. It was only many years later, as I myself pursued the study of Chinese medicine, that my memory of that time reawakened.

Many people have asked me why I gave up modern medicine to study Chinese medicine, a field at the time ostracized and despised by society. I usually answer: First, I was weak and sickly during my childhood, and treatment with modern medicine proved useless; second, since my entire family consists of doctors, I grew up always surrounded by many books, including those about Chinese herbs as well as other herbs. I truly think that I finally devoted myself to such study because it was destined and not because of the answers that I gave my questioners. Except for chance, I would probably not have devoted myself to the study of Chinese herbal medicine.

Thinking over my career, I can recall numerous times when I have cured fellow doctors with Chinese herbs. All of them took Chinese herbs when sick, yet never took up the study of Chinese medicine. In fact, of the many doctors born into medical families and surrounded by Chinese herbs, only a few, such as myself, have ever given up modern medicine to devote themselves to the study of Chinese herbal medicine.

One morning in March of 1927, as usual before seeing patients, I was reading the literature section of the Tokubai newspaper. There I saw a review of a book entitled A New Study of Kampo Medicine by Tadano Nakayama. After reading the review, I immediately ordered the book. The review mentioned that the autumn edition of the magazine Japan and the Japanese had carried an article by Nakayama "On the Revival of Chinese Herbal Medicine." Because of the sensation it caused, he had expanded that article into this book.

For years I had looked down upon Chinese herbal medicine, but after reading this book I realized that its approach was as clinical and valid as modern medicine. I was ashamed of my ignorance-I had thought it to be only folk medicine. Through reading this book I learned of the classic Shanghan Lun, the oldest book of treatment in the world.

One day, I saw an announcement of the publication of the first volume of a magazine called Kokan Igaku (June 1927). I immediately ordered it. Although not a wealthy man, the herbalist, Yumoto, who later became my teacher, published the magazine himself. After reading it, I decided to devote my life to Chinese herbal medicine.

Yumoto had graduated from Kinzawa Medical School (a Western medical school) in 1901. His attitude towards the value of the medical practices changed, however, and he gave up modern medicine to study Chinese herbal medicine. At the time (around 1920), there were no Chinese herbal specialists left in practice, but some medical doctors had decided to study the subject, even while maintaining their Western medical practice. A licensed medical doctor would be able to prescribe Chinese herbal medicine, but a Kampo specialist lacking Western medical training could not, because he would have no license to practice.

Along with the gradual revival of Kampo medicine via practitioners of modern medicine, another development helped the field to grow: modernization of the dosage form of herbal medicine. In the 1920s, Nagakura, a pharmaceutical company headed by Nagakura Onzo, began developing ways to mass produce Chinese medicine using precision apparatus and scientific methods. This led to the production of dried decoctions in a convenient granular form, commonly called wakan-yaku (Japanese-style classic remedies) that have become a standard method of Kampo medicine administration. In place of a set of small drawers containing a limited number of crude herbs to be selected, weighed, and then sent home with the patient for preparation as a decoction, the manufactured herb formulas were dispensed in a convenient form and simply given to the patient in quantities that would last until the next visit. At about the same time, Tsumora Juntendo, a company founded by Jusha Tsumura in 1893, established a research institute and herbal garden to promote the development of Kampo.

Thus, with some doctors learning Kampo, the publication of some Kampo books and journals, the offering of a Kampo course at a medical college, and production of modern herbal preparations, this field of medicine was ready to expand substantially. Shinichiro Takeyama wrote Kampo-ijutsu-fukko-no-riron (Theories on the Restoration of Kampo Medicine) in 1941, ushering in the new age of Kampo practice.

Then, World War II put the development of Kampo into the background. Modern medicine, especially surgery and antibiotic therapy, was critical during the war years. When Japan was defeated in 1945, it took several years for the country and its industrial and social activities to recover. The medical doctors who had taken up the practice of Kampo formed the Japan Society for Oriental Medicine in 1950 with 98 members. This organization helped lead the way to the current restored form of Kampo; it currently has about 10,000 members. The work initiated in the 1920s to develop prepared forms of Kampo medicine progressed further to allow for large scale production in the 1950s.

In 1967, four Kampo remedies were approved for reimbursement under Japan's national health insurance. In 1976, the Japanese government gave official approval to 82 prescriptions of the Kampo system; these could be purchased under the National Health Insurance System and were available as over-the-counter remedies. In addition, the Department of Pharmaceutical Affairs of the Ministry of Health and Welfare approved 210 herbal formulas (including the 82 already mentioned) for use in medical facilities, where they were also available over-the-counter (but not all of them were approved for coverage by national health insurance). These formulas were adopted as medicines without having to go through the lengthy registration process that was required for modern drugs (and also required for any other herb formulas). Specifically, the long history of use of these formulas was cited as sufficient evidence for their safety, if not for their efficacy, so the accumulation of safety documentation normally required was waived. Today, 148 prescriptions are covered by the national health insurance and more than half of them are the focus of modern Kampo practice.

Aside from the formulas that had been adopted several centuries earlier by the Goseiha and Kohoha schools, a few prescriptions of the Warm Disease school that had developed in China during the 18th Century were also included among the approved formulas. The main influence from this school was the Wenbing Tiaobian (Systematic Differentiation of Warm Diseases; published 1798) written by Wu Jutong (also known as Wu Tang); he presented the popular Lonicera and Forsythia Formula (Yin Qiao San) and Morus and Chrysanthemum Combination (Sang Ju Yin), both used for the wind-heat type of ailment. In addition to the approved formulas, all of the individual herbs that go into making the formulas are also approved for use, so that modified formulations, produced by combining single herbs with base formulas or combining only single herbs to make new formulas, are also available for prescription.

Kampo spread rapidly during the period 1985-1995; after that, the number of practitioners stabilized at a nearly constant level. By 1985, it was reported that about 20-25% of the medical doctors in Japan were including some herb prescribing in their practice. However, as pointed out by Terasawa Katsutoshi, only about 100 or so doctors were routinely prescribing Kampo medicines to their patients. The proportion of doctors that provide some Kampo medicines has risen to about 50% or more by some estimates, with a proportional increase in Kampo specialists (more than 200). In addition, there are about 10,000 pharmacies in Japan that dispense herb formulas. About 2% of total drug expenditures in Japan are herbal medicines, the largest part of them provided by Tsumora Juntendo, with contributions from about 20 smaller manufacturers. Kampo medicine research is conducted at the Toyama Medical and Pharmaceutical University in Toyama, the Kitazato Institute in Tokyo, and the Kinki University Medical Teaching Hospital near Osaka, as well as at other sites. Surveys conducted in Japan have revealed that the main uses of Kampo medicines are treatment of hepatitis, menopausal syndrome, common cold and other upper respiratory tract infections, autonomic nervous dysfunctions, constipation, cough and asthma, skin diseases (mainly eczema and other categories of dermatitis), lumbago and neuralgia, and gastro-intestinal disturbances.