Li Shizhen heard that there is a kind of flower in the north called Datura stramonium, which will make people laugh and dance, and even be anesthetized in severe cases. Li Shizhen left his hometown to look for Datura flowers in the north. Finally, he found a stem four or five feet high, with leaves like eggplant leaves, flowers like morning glory, and Datura flowers that bloom at night. In order to master the performance of Datura, he personally tried to "give it a try". And wrote, "If you cut the moxibustion fire, you should take it first, so you won't feel bitter." According to modern pharmacological analysis, Datura contains scopolamine, which can excite the brain and medulla oblongata on the central nervous system and antagonize or paralyze the parasympathetic nerves on the peripheral nerve. Now there is a medicine called 654-2 for relieving gastrointestinal spasm, and the ingredient is scopolamine.
In order to identify Agkistrodon acutus, regardless of the risk, Li Shizhen followed the snake catcher up the mountain to catch snakes and made them into medicinal materials. After careful observation of the shape of Agkistrodon halys, it is found that the head of Agkistrodon halys is triangular, with four fangs in its mouth and 24 diagonal squares on its back. (Now it is called Fang Shengwen for character recognition) It is really different from ordinary snakes. According to the characteristics of Agkistrodon acutus in expelling wind, Li Shizhen prepared Agkistrodon acutus medicinal liquor to treat hemiplegia and stroke. According to modern pharmacological analysis, it is proved that Agkistrodon acutus extract has sedative, analgesic, vasodilator and antihypertensive effects.
For details, please download: Li Shizhen's Method of Studying Materia Medica.