Why did Rudolf Virchow question the idea that bacteria always cause disease?

Rudolf Virchow’s skepticism toward the emerging field of bacteriology was rooted in his commitment to rigorous scientific evidence. He argued that the mere presence of a microorganism in a patient did not necessarily prove that the organism was the causative agent of the disease.1

Virchow maintained that disease processes were fundamentally cellular in nature, a concept he pioneered through his work in cellular pathology. While he was resistant to the idea that bacteria were the sole cause of disease, he demonstrated a forward-thinking perspective by suggesting—long before they were formally discovered—that some bacteria might produce toxins that contribute to illness. His cautious approach reflected a desire to distinguish between correlation and causation in medical research.12