Herbal medicine, also known as phytomedicine, refers to the use of plants for medicinal purposes. The use of plants as medicine predates recorded history and is still the most widely used system of medicine. Herbal medicines are made from specific plants, with the therapeutic effects of each plant owing to its complex chemical nature. The use of herbal medicine is increasing in conventional medicine due to improvements in analysis and quality control, together with clinical research validating it in treating and preventing disease. Interestingly, many modern pharmaceuticals contain chemicals that have been derived from plants. For example, the heart medication digoxin is derived from the foxglove plant (Digitalis purpurea).