Yamagiwa Katsusaburō (山極 勝三郎, 23 February 1863 – 2 March 1930) was a Japanese pathologist who carried out pioneering work into the causes of cancer, and was the first to demonstrate chemical carcinogenesis.

He was appointed as a professor at the Medical School, Imperial University of Tokyo and published his landmark work, Byōri Sōron Kōgi, in 1895.

[2][5] In a series of experiments conducted in 1915, Yamagiwa and his assistant Kōichi Ichikawa (1888–1948) induced squamous cell carcinomas on the ears of rabbits using coal tar, demonstrating the latter's carcinogenic properties.

[6][7][8][9][10] Two years later, Katsusaburo Yamagiwa successfully induced squamous cell carcinoma by painting crude coal tar on the inner surface of rabbits' ears.

[12] In 1966, the former committee member Folke Henschen advocated that Yamagiwa deserved the Nobel Prize, but it was not realized.