At the beginning of the 19th century, medicine was based largely on speculative and philosophical concepts. The greatest merit of Rudolf Virchow was without doubt a way of thinking based on natural science. In place of the empirical chaos represented by the doctrines of humors and crasis, he created the new paradigm of cellular pathology. In the field of inflammation, he critically analyzed the meaning of the four key symptoms of inflammation (redness, swelling, heat and pain) and postulated that inflammation cannot be represented as a single process but rather constitutes various inflammatory processes. In addition he introduced the functio laesa , denoting the restricted function of inflamed tissues. In the pathogenesis of inflammation, Virchow highlighted the importance of the inflammatory stimulus. The irritatio is the starting point and the conditio sine qua non . Through his pathohistological investigations in experimental animals and in humans, inflammation was widely accepted as the central cause of atherosclerosis, until the end of the 19th century, and has been confirmed in recent decades. It was Virchow who first coined the term endarteriitis deformans . Likewise, he was also the first to hypothesize a link between microinflammation and subsequent cancer development. This hypothesis has recently been corroborated by numerous studies and may have therapeutic consequences. Virchow contributed to nearly all aspects of human pathology and championed the cause of social medicine.