Arthur Eichengrün (13 August 1867 – 23 December 1949) was a German Jewish chemist, materials scientist, and inventor. He is known for developing the highly successful anti-gonorrhea drug Protargol, the standard treatment for 50 years until the adoption of antibiotics, and for his pioneering contributions in plastics: co-developing (with Theodore Becker) the first soluble cellulose acetate materials in 1903, called "Cellit", and creating processes for the manufacture of these materials which were influential in the development of injection moulding. During World War I his relatively non-flammable synthetic cellulose acetate lacquers, marketed under the name "Cellon", were important in the aircraft industry. He contributed to photochemistry by inventing the first process for the production and development of cellulose acetate film, which he patented with Becker.
Eichengrün claimed to have directed the initial synthesis of aspirin in 1897, but his claim has been disputed. For many years Bayer credited Felix Hoffmann, Eichengrün's junior, with the invention of aspirin. However, the first attribution of the discovery to Hoffmann appears in 1934, and may have reflected anti-Jewish revisionism.
During World War II, Eichengrün was imprisoned in the Theresienstadt concentration camp.