Complex sentence: The clinical application of antimicrobial agents is traditionally known as chemotherapy, a term coined in the early 1900s by Paul Ehrlich; to distinguish it from oncological chemotherapy, it is sometimes known as antimicrobial chemotherapy or antiinfective chemotherapy.
Split into simpler sentences: The clinical application of antimicrobial agents was originally known as chemotherapy, a term coined in the early 1900s by Paul Ehrlich. To distinguish this from oncological chemotherapy, the therapeutic use of antimicrobials is now known as antimicrobial chemotherapy or antiinfective chemotherapy.