Over-the-counter drugs (OTC) refer to those drugs that consumers can buy directly in pharmacies or pharmacies without a doctor's prescription, and vice versa. Over-the-counter drugs, converted from prescription drugs, are drugs with long-term application, confirmed efficacy, stable quality and safety for non-medical professionals.

Over-the-counter drugs, converted from prescription drugs, are drugs with long-term application, confirmed efficacy, stable quality and safety for non-medical professionals. But over-the-counter drugs have a more detailed classification. The one with white characters on the red background is Class A, and the one with white characters on the green background is Class B. Although both Class A and Class B OTC can be bought in pharmacies, Class B OTC is safer.

According to the Administrative Measures for the Classification of Prescription Drugs and Non-prescription Drugs (Trial), OTC words designated by the state must be printed on the packaging of non-prescription drugs. For non-prescription drugs entering the field of drug circulation, enterprises should conspicuously print corresponding advice on drug packaging or drug instructions. The specific content is: "Please read the drug instructions carefully and use them according to the instructions or purchase and use them under the guidance of pharmacists".