In 1880, as the first in Poland and second in the world he succeeded in surgical removal of the pylorus in a patient suffering from stomach cancer.

Rydygier proposed (1900) original concepts for removing prostatic adenoma and introduced many other surgical techniques.

Due to Prussian harassment, in 1887, he renounced Prussian citizenship, and obtained Austrian citizenship, and sold his clinic in Chełmno to Leon Polewski, one of his employees (Rydygier already lived in the Austrian Partition of Poland).

He didn't leave Lwów, even when he was offered to move to Charles University in Prague.

In 1899 in Lwów, Polish doctors celebrated the 25th anniversary of Ludwik Rydygier's scientific activity.

[4] Numerous hospitals in Poland are named after him, including in Kraków, Częstochowa,[2] Toruń, Łódź, Suwałki.

Also the Collegium Medicum in Bydgoszcz and a lecture hall of the Medical University of Gdańsk bear his name.