Another vital role fore the rainforest is in providing a number of the natural products that are used in the pharmaceutical industry.Many of the essential ingredients in medicines for heart disease,asthma,arthritis,and pneumonia are derived from plants that aare only found in tropical foress.Todate, over two housand tropical plants have been identified by scientists as having anti-cancer properties, and the Rosy Periwinkle,a plant that is only found in South American rainforests,is used in the treatment of childhood leukemia.