was a Japanese medical doctor working as a medical scientist who discovered tranexamic acid in the 1950s in her quest to find a drug that would treat bleeding after childbirth (post-partum haemorrhage). After publishing results in 1962 she became a chair at Kobe Gakuin University, where she worked from 1966 until her retirement in 1990. Okamoto's career was hampered by a very male dominated environment.
During her lifetime she was unable to persuade obstetricians at Kobe to trial the antifibrinolytic agent, which had become a drug on the WHO list of essential medicines in 2009. She lived to see the 2010 beginning of the study of tranexamic acid in 20 000 women with post-partum haemorrhage, but died before its completion in 2016 and the publication of tranexamic acids fatality preventing results in 2017, that she had predicted.