A surprising large number of modern-day medicines rely on plant-based ingredients. Up to 70,000 plants in the world are believed to have medicinal value, yet the pharmaceutical industry has not yet recognized the extent of their potential. Some 1,000 plants are commercially cultivated, while most are harvested in the wild, in some cases, to the brink of extinction. Reporter Hilke Fischer headed to Kenya to explore the fate of the Prunus Africana, a tree containing medicinal properties and active ingredients considered effective against various illnesses, especially prostate cancer. Environmental groups are working with the local population to help replenish the valuable trees. In our background article, Tamsin Walker looks at the current role and treatment of medicinal plants and asks why they are so often ignored.