Li Shizhen was a man from China who lived a long time ago, hundreds of years ago! He was a very smart person who knew a lot about plants and how they can be used to help people when they are sick.
Li Shizhen wrote a very big and important book called the Compendium of Materia Medica. In this book, he wrote about more than 2000 different kinds of plants that can help people with their health problems. He also wrote about 11,000 different ways to use these plants to make medicines.
Just like how we go to the doctor when we are sick, people would go to Li Shizhen to ask for his help. He would use his knowledge of plants to make special remedies for them to help them feel better.
Today, Li Shizhen's book is still very important and is used to help people all around the world. He is remembered as a great doctor and a wise man who helped many people feel better.