When first introduced, hospital scrubs (or hospital scrubbe sets) were known as 'surgical greens'; since they were initially only available in green, and were used exclusively by operating room staff (for pre-op 'scrub-in') prior to surgery.

Being both practical and comfortable, not surprisingly surgical scrubs became normal wear for surgeons and nurses while working throughout the hospital; soon to be joined by non-surgical doctors, then administration, maintenance and hospital technicians.

With their broader use throughout the hospital, surgical scrubs (or surgical greens) became known as just 'scrubs'.  Any reference to the 'green' descriptor was eventually dropped once retailers began to offer scrubs in various colors; followed by unique scrub prints & patterns (from geometric patterns, to cartoons to holiday themes)!  Going even further, some retailers now offer customizable scrubs where you can special order details such as extra pockets, elasticized drawstring, personalized embossing, etc.!

With such wide adoption by workers across all the various departments, hospital scrubs became the de facto uniform for virtually all medical & hospital employees.  Eventually, members of the various hospital staff groups & departments began to select 'group' scrub uniforms unique in color and/or styling for identification purposes.  For example, in most hospitals you will find that nurses have standardized nursing scrub uniforms that are distinct from doctors, technicians and other hospital staff - thus making identification by patients and other hospital staff much easier.

Given the comfort, functionality and affordability of scrub pants & scrub uniforms, it is of little surprise that hospital scrubs eventually were adopted by mainstream consumers.  For example, certain activities (lounging around the house; sleeping; fitness club/class) lend themselves to the functionality and comfort of scrubs; as do particular consumer segments - such as college students who seem a natural fit.  Perhaps the most obvious evidence of scrub pants & scrub sets successfully penetrating the consumer market is the sheer volume of inline scrub retailers!  And on that note...