<P> As of 2011, around a third of older adults in the U.S. reportedly use OTC drugs . By 2018, the prevalence of use by adults in the U.S. as first - line treatment for minor illnesses had reached 81% . </P> <P> In Canada, there are four drug schedules: </P> <Ul> <Li> Schedule 1: Requires a prescription for sale and are provided to the public by a licensed pharmacist . </Li> <Li> Schedule 2: Does not require a prescription but requires an assessment by a pharmacist prior to sale . These drugs are kept in an area of the pharmacy where there is no public access and may also be referred to as "behind - the - counter" drugs . </Li> <Li> Schedule 3: Does not require a prescription but must be kept in an area under the supervision of a pharmacist . These drugs are kept in an area of the retail outlet where self - selection is possible, but a pharmacist must be available to assist in the self - selection of medication if required . </Li> <Li> Unscheduled: Does not require a prescription and may be sold in any retail outlet . </Li> </Ul> <Li> Schedule 1: Requires a prescription for sale and are provided to the public by a licensed pharmacist . </Li>

Where did the phrase over the counter come from