Medicinal plants have been identified and used throughout human history. Plants have the ability to synthesize a wide variety of chemical compounds that are used to perform important biological functions, and to defend against attack from predators such as insects, fungi and herbivorous mammals (Babalola, 2009). Chemical compounds in plant mediate their effects on the human body through processes identical to those already well understood for the chemical compounds in conventional drugs; thus herbal medicines do not differ greatly from conventional drugs in terms of how they work. This enables herbal medicines to be as effective as conventional medicines, but also gives them the same potential to cause harmful side effects.  Ethnobotany  (the study of traditional human uses of plants) is recognized as an effective way to discover future medicines. In 2001, researchers identified 122 compounds used in modern medicine which were derived from ethnomedical plant sources (Babalola, 2009). Many of the pharmaceuticals currently available to physicians have a long history of use, as herbal remedies, including aspirin, digitalis, quinine and opium. Treatment of diseases is almost universal among non-industrialized societies, and is often more affordable than purchasing expensive modern pharmaceuticals (Beltrame et al., 2002). The World Health Organization (WHO) estimates that 80 percent of the population of some Asian and African countries presently use herbal medicine for some aspect of primary health care (Beltrame et al., 2002). Studies in the United States and Europe have shown that the use of herbal madicine is less common in clinical settings, but has become increasingly more in recent years as scientific evidence about it effectiveness has become more widely available.