OTC belongs to the non-prescription drugs, there is a corresponding symbol of the drug, is not required to clinicians to prescribe, directly to the pharmacy to buy can, under the guidance of the pharmacist in the pharmacy or in accordance with the instructions for standardized application. OTC drugs belong to the non-prescription drugs, including OTC Class A and OTC Class B. OTC Class A drugs are relatively strict and need to be applied under the guidance of a licensed pharmacist in a pharmacy, while OTC Class B drugs can be applied according to the instructions. OTC drugs themselves have been through long-term clinical trials, are safe, easy to store, efficacious, do not have obvious toxicity and addiction, without the need for clinicians to prescribe. Although OTC drugs do not require a prescription, they still need to be applied in accordance with the guidance of a licensed pharmacist and the instructions to prohibit abuse and cause unnecessary damage to the body.