1. Who decided whether a plant was poison or medicine? The legend of Shennong
There is a legend from ancient China about a figure named Shennong. According to the story, he tasted wild plants himself to distinguish between poisons and medicines. The medical book *Shennong Bencao Jing* (*Shen Nong Ben Cao Jing*) was named after him [8].
Historically, Shennong is a legendary figure, not a confirmed person. The time when the book was compiled is debated, with theories ranging from the end of the Former Han dynasty to the 2nd or 3rd centuries [1]. What is clear is that the book was not the discovery of one person, but a collection of experiences gathered over a long time.
2. How the Shennong Bencao Jing divided 365 medicines into three grades
The *Shennong Bencao Jing* included 365 types of medicine, matching the number of days in a year. These were divided into three categories: 120 "Upper" (Superior), 120 "Middle", and 125 "Lower" (Inferior) [1].
The general guideline for this division was the strength of the medicine. "Upper" medicines were for health maintenance and were considered to have few harmful effects even with long-term use. "Middle" medicines could be used for maintenance or treatment depending on how they were used. "Lower" medicines had strong effects but were toxic and could not be used for long periods; they were for treatment only. However, this was the view at the time, and it does not mean "Upper" medicines are always safe.
Ginseng and licorice are listed as "Upper", kudzu root and ephedra as "Middle", and rhubarb and monkshood as "Lower" [1]. Even in the first book, the familiar names of today's herbal medicines were already present.
This book grew over time. Around 500 CE, Tao Hongjing expanded the list to 730 types, but the three-grade classification was kept [9]. Later, Li Shizhen of the Ming dynasty traveled to various places and interviewed people, taking 27 years to compile the *Bencao Gangmu* (*Ben Cao Gang Mu*), completed in 1578. It is said to contain 1,892 types, with 374 added by Li Shizhen himself [7].
Note: Do not assume that "Upper" grade means safe. Read these classifications as the historical perspective of the time, not as modern safety guarantees.
3. Kakkonto: how 7 herbs were combined into one medicine in the Shanghan Lun
The *Shanghan Lun* (*Shang Han Lun*), said to be written by Zhang Zhongjing at the end of the Later Han dynasty in the 3rd century, is a treatment guide for sudden febrile diseases. It contains prescriptions associated with Zhang Zhongjing and was compiled and passed down through later eras. It includes prescriptions like Kakkonto, which are still used today [2].
Kakkonto is a prescription that combines 7 types of herbs: kudzu root, ephedra, ginger, jujube fruit, cinnamon bark, peony root, and licorice [10]. This shows that medical practice had moved from selecting single medicines to combining them for use.
4. The 60 medicines offered to the Great Buddha at Todai-ji in 756
In 756 (the 8th year of Tenpyo Shoho), Empress Komyo offered 60 types of medicinal substances to the Great Buddha at Todai-ji Temple on the 49th day after the death of Emperor Shomu. The purpose was to honor the Great Buddha and to provide medicine to help those suffering from illness [3].
All 60 types are listed in a catalog called the *Shushinyocho* (*Shu Shi Nyo Cho*). These are called "catalog medicines". The names of the medicines and the actual items remained together as a set.
5. The 1948 survey of the Shosoin medicines and what it found
From 1948 for about 4 years, a group of experts including Yasuhiko Asahina seriously examined the medicines preserved in the Shosoin. A second survey was conducted in 1994–1995. Of the catalog medicines, about 39 types (38 types according to some records) remain today, and 24 types of non-catalog medicines were also confirmed [3][4].
The analysis showed that ginseng contains ginseng saponins (ginsenosides), licorice contains glycyrrhizin, and rhubarb contains sennosides [4]. This means that medicines from over 1,200 years ago contained the same types of ingredients as today's herbal medicines.
However, the research only confirmed that these ingredients were detected. It does not mean that the effects were exactly the same as they are today.
Note: The number of existing medicines varies by one depending on the source, so it is safer to read the number as "about 40 types" [3].
6. How Nagai Nagayoshi isolated ephedrine from the Ephedra plant
Nagai Nagayoshi, from Awa (Tokushima), received a Kampo (traditional Chinese medicine) education from his father in childhood and later became interested in chemistry through Western learning. He studied in Germany and, after returning to Japan, focused on researching the components of Kampo herbs. He was also the first chairman of the Pharmaceutical Society of Japan [5].
Nagai is said to have discovered the active alkaloid, ephedrine, from Ephedra in 1885 (the 18th year of Meiji). Some dictionaries list the year as 1887. Ephedrine was found to have effects such as widening the bronchi and is used in treatments for asthma and as a cough suppressant in cold medicines [5].
7. How the Japanese Pharmacopoeia's national standards protect herbal medicine quality
The Japanese Pharmacopoeia is a book of standards set by the government to ensure the quality of pharmaceuticals. The first edition was published in 1886 (the 19th year of Meiji). It also includes general rules for crude drugs. In the 18th revision (Reiwa 3, 2021), there were 2,033 pharmaceutical items, of which 327 were crude drugs [6].
In hospitals, Kampo preparations are used. At the time of one source's publication, 148 types of medical Kampo preparations (147 oral, 1 external) were listed in the drug price standards, along with 159 types of crude drugs for decoctions (the numbers change by year) [11].
8. How to investigate further: finding herbal ingredients on medicine boxes at home
You can look at the "Ingredients" section on boxes of cold medicine or Kampo medicine at home. You might find names like kudzu, ephedra, or licorice. You only need to look; there is no need to take the medicine.
At the library, open an illustrated guide to Kampo or crude drugs to see photos of the plants and trees that medicines come from. Searching for whether a medicine appears in old books can lead to new discoveries.
The concepts of the Japanese Pharmacopoeia can be checked on the Ministry of Health, Labour and Welfare website. For how to use medicines, please consult a doctor or pharmacist.