The analysis of Zinaida Ermolieva’s scientific activity has been carried out since 1921. An important aspect was also the fact that in 1925 Ermolieva singled out and studied a cholera-like vibrio, which had an unusual ability to glow in the dark. Investigating the nature of this phenomenon, she organized the first in the Soviet Union laboratory of biochemistry of microbes at the Biochemical Institute. In 1942, Ermolieva and her co-workers at the All-Union Institute of Epidemiology and Microbiology found an active producer of penicillin and isolated the first Soviet antibiotic, penicillin-crustosin. A method for the isolation and concentration of lysozyme was developed, and its chemical nature was established and new sources of the enzyme, including plant sources, were discovered. Getting penicillin served as an impetus for the development and introduction of other antibiotics into clinical practice. Under the guidance of Zinaida Ermolieva was created: streptomycin, tetracycline, levomycetin, ekmolin, ecmonovicillin, bicillin, combined preparations of antibiotics.