The chemical/mechanical model of the body led not only to improvements in surgery, but also to the development of drugs that both prevented and treated disease. Over time the chemically active components of many of the ancient herbal remedies were derived and new more effective drugs produced. Much of the chemical history of medicine from the seventeenth century onward is about identifying the cause, and very often the chemical cure for disease. Today infectious diseases are no longer the primary cause of death in developed countries.