The OTC shelf needs no doctor; the prescription shelf does
The national regulation draws the line a visitor at a 药店 (pharmacy) needs: a prescription drug may be dispensed, bought and used only on a licensed physician's or licensed assistant physician's prescription, while a non-prescription (OTC) drug may be judged, bought and used on your own without one. So the OTC shelf is buy-without-a-doctor; the prescription counter is not.
Article 2
Source: State Drug Administration (国家药品监督管理局) Order No. 10, in the national regulations library on the Central People's Government portal 中国政府网 (www.gov.cn) — 处方药与非处方药分类管理办法(试行)(Measures for the Classified Administration of Prescription and Non-Prescription Drugs, Trial), Articles 2, 7, 8, 11 (source issued 1999-06-18 by SDA Order No. 10; effective 2000-01-01; read August 1, 2026)