For 2,200 years until 1805, medicine was practised exclusively according to the ancient Greek physician Hippocrates (460-377 BC), the founding father of natural medicine. He taught that the first and foremost principle of medicine must be to respect nature’s healing forces, which inhabit each living organism. Hippocrates considered illness a natural phenomenon that forced people to discover the imbalances in their health. He strongly believed in good food and related the course of any ailment to poor nutrition and bad eating habits. He stressed, "Let food be your medicine and medicine be your food"–advice that, to this day, has not lost its validity.