For centuries, people chewed willow tree bark to relieve pain, but scientists at chemical firm Bayer didn’t isolate its active ingredient until the 1800s and eventually patented its modified version as Aspirin. Aspirin is just one example of a medicine derived from natural sources. In fact, the World Health Organization estimates that around 40% of modern pharmaceutical products have roots in remedies used by our ancestors. Even with this impressive success of harnessing nature’s bounty, scienti...