A natural antibiotic is a substance that has naturally occurring antibiotic properties, according to Mother Earth News. These substances are usually plant-based.
The first antibiotic recognized by medical science was a naturally growing mold that had evolved a resistance to bacteria over time, according to the American Chemical Society. Years of research, growth and concentration of the chemical found in this rare type of mold eventually led to the manufacturer of penicillin as a treatment for a variety of bacterial infections.
There are many other plants found in nature that have antibiotic properties, according to The Doctor Oz Show. These plants include, golden seal, Oregon grape and Andrographis paniculata.