Just watched a fascinating program about a scientist (Gary Strobel) who has been searching the globe for endophytes that grow in plants, and are often used by the local people to treat illness of various sorts. Each organism is unique when viewed with a scanning electron microscope, and has the potential to be used against many different diseases.
http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=104473
http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=104473