How long ago did people start using plant products as medicine?

People have been using plant products as medicine for thousands of years, with evidence suggesting that medicinal plant use dates back at least 5,000 years. Ancient civilizations, such as those in Egypt, China, and India, documented the use of herbal remedies in their medical texts. The practice has continued to evolve, laying the foundation for modern pharmacology and herbal medicine. Today, many contemporary medicines are derived from plants or inspired by their chemical compounds.