In order that this discussion may be limited to the field in which I am primarily concerned and in which I have had some degree of experience, consideration will be directed to the groups of animal parasites referred to as the protozoa and the helminths. Some of the drugs available for treating animal parasites, particularly certain anthelmintics, are a heritage from the ancients of the Old World and from the Amerinds;1 others, particularly certain antiprotozoan drugs, are of recent origin or recent application to parasitoses of the human body. For the most part, use of the former group is based primarily on clinical experience without antecedent pharmacologic assay, while clinical use of most of the latter group has been a sequel to adequate tests in the laboratory.
It is almost axiomatic to state that a suitable chemotherapeutic is one which is as nearly specific as possible within the limits
FAUST EC. THE CHEMOTHERAPY OF INTESTINAL PARASITES. JAMA. 1941;117(16):1331–1335. doi:10.1001/jama.1941.02820420023007