Bayer AG is a German company best known for their development of aspirin, yet for as famous as they are, few people know the dark history Bayer has. First founded in 1863 by Friedrich Bayer after discovering aspirin, Bayer AG would go on to become one of the largest chemical and pharmaceutical companies in the world.
The company grew until they were purchased by IG Farben, another German chemical company. IG Farben used intense slave labor in their factories, most notably at Mauthausen-Gusen concentration camp, and during the Nazi regime had few human rights restrictions to follow. In fact, IG Farben produced 42.5% of the chemical used in the gas chambers of various concentration camps in Germany.
When they purchased Bayer they continued to use human test subjects, and many of the chemicals that were being tested, both to help and hurt humans, were tested on human subjects. Bayer became known for this practice and by the end of the war the Bayer executive, Fritz ter Meer, was arrested and imprisoned for crimes against humanity.