A regimen is a plan, a regulated course such as a diet, exercise or medical treatment, designed to give a positive result. A low-salt diet is a regimen. A course of penicillin is a regimen.
The work, Regimen in Acute Diseases, attributed to the ancient Greek physician, Hippocrates of Cos, describes the types and usage of medical regimens in his era (400 BCE). This is perhaps the first appearance of the term.
In economic statistics, a regimen refers to the selected goods and/or services priced for the purpose of compiling a price index. The most wellknown example is the consumer price index.