There are multiple definitions - click on the translation that matches your context.

不用处方的药物

形容词

full

over-the-counter

adjective

Definitions of over-the-counter

the selling of non-prescription drugs (=drugs that you can buy without first having to see a doctor)

Many drugs will be available over the counter instead of by doctor's order only.

trading of stock by dealers through telephone and computer contacts directly instead of via a securities exchange

The brokers do a lot of over the counter trading on behalf of their smaller clients who are not listed on the stock exchange.