Józef Dietl (24 January 1804 in Podbuże near Sambor – 18 January 1878 in Kraków) was an Austro-Polish physician born to an Austrian father and Polish mother. He studied medicine in Lviv and Vienna. He was a pioneer in balneology, and a professor of Jagiellonian University, elected as its rector in 1861. Dietl described the kidney ailment known as "Dietl's crisis" as well as its treatment.
He is renowned worldwide for being a "reformer of medicine" since he demonstrated through experiments that bloodletting was useless if not dangerous.[1][2] His experiments were based on the use of a control group, a procedure still used today in the so-called "clinical trials" foundation of evidence-based medicine.[3]