French-born American microbiologist, environmentalist, and author whose pioneering research in isolating antibacterial substances from certain soil microorganisms led to the discovery of major antibiotics (antibiotic). Dubos is also known for his research and writings on a number of subjects, including antibiotics, acquired immunity, tuberculosis, and bacteria indigenous to the gastrointestinal tract. In his later years his interest shifted to man's relationship to the natural environment.

In 1921 Dubos graduated from the Institut National Agronomique in Paris. Three years later he emigrated to the United States and continued his studies at Rutgers University (Ph.D., 1927). He then joined the Rockefeller Institute for Medical Research in New York City, where he spent most of his career, becoming a professor in 1957 and professor emeritus in 1971.

In 1930 Dubos isolated from a soil microorganism an enzyme that could decompose part of the bacillum that causes lobar pneumonia in humans. The enzyme subsequently proved to have a therapeutic effect on laboratory animals with that disease. In 1939 Dubos isolated another antibacterial substance and named it tyrothricin. This substance, which he was able to chemically analyze, became the first antibiotic to be commercially manufactured, though it soon proved too toxic for large-scale use. Dubos's researches and techniques stimulated interest in penicillin and led Selman Waksman (Waksman, Selman Abraham), Albert Schatz, and Elizabeth Bugie to isolate streptomycin.

Dubos's works include Bacterial and Mycotic Infections in Man (1948), Pasteur and Modern Medicine (1960), Man, Medicine, and Environment (1968), and So Human an Animal (1968; Pulitzer Prize, 1969). He was for many years an editor of the Journal of Experimental Medicine.