One hundred years ago, in 1909, Theodor Kocher was awarded the Nobel Prize in Physiology and Medicine for his work on the physiology, pathology, and surgery of the thyroid gland. In the late 19th century, the resection of the thyroid was feared because of its high mortality rate. Kocher's innovative techniques resulted in safe outcomes. His observations that radical resection of the thyroid results in 'cachexia strumipriva' contributed to the recognition that the thyroid is essential for normal growth, development and metabolism. He made many other seminal contributions to the field of surgery and medicine, and his expertise was internationally recognized. Kocher served as the chairman of surgery at the University of Bern in Switzerland, his alma mater, until his death in 1917.