Thorvald John Marius Madsen (February 18, 1870 in Frederiksberg – April 14, 1957 in Gjorslev) was a Danish physician and bacteriologist.

From 1916 onwards Madsen did several inspection visits to detention centers in Russia, where conditions were highly questionable.

During these travels brought Thorvald Madsen, among other things excess serum against various diseases.

In addition, Madsen helped more Danish-Schleswigers, who had been in German military service and ended up a prisoner of war.

[1] In the years 1921-1937 was Thorvald Madsen, president of the League of Nations Health Committee.