ruth ella moore (may 19, 1903 in columbus, ohio – july 19, 1994) was a bacteriologist, who in 1933 became the first african-american woman to gain a phd in a natural science. she was a professor and head of the department of bacteriology at howard university, publishing work on tuberculosis, immunology and dental caries, the response of gut microorganisms to antibiotics, and the blood type of african-americans. during that period she was promoted to associate professor. though there are gaps in howard’s personnel records, moore is believed to have continued to teach and conduct research on bacteriology at howard until she retired in 1973.