Over-The-Counter Products(OTC) drugs are medicines that may be sold without a prescription, in contrast to prescription drugs. The name "over-the-counter" is somewhat confusing to some, since these items are found on the shelves of stores and bought like any other packaged product, while prescription drugs are sold at a pharmacy counter. The term likely dates back to before self service shopping became common, when most goods were obtained by requesting them from a clerk at a sales counter; while prescription drugs required a visit to the doctor first, these drugs could be purchased "over the (sales) counter" just like other goods Azo Cranberry Tabs, Polident Denture Tab.

In the United States, the manufacture and sale of OTC substances is regulated by the FDA. The Federal Food, Drug, and Cosmetic Act requires that all "new drugs" are required to obtain a New Drug Application ("NDA") prior to entering interstate commerce, but the act exempts any drugs generally recognized as safe and effective ("GRAS/E") from this requirement. In order to fit the vast amount of OTC drugs that were already on the market prior to the requirement that all drugs obtain an NDA, the FDA created the OTC monograph system to review classes of drugs and categorize them as GRAS/E by regulation. This meant that certain classes of Over-The-Counter Products were not required to obtain an NDA and could remain on the market.

Thus, manufacture must be done either pursuant to an FDA monograph, which specifies types of Over-The-Counter Products, active ingredients and labeling requirements, or pursuant to a New Drug Application (NDA), for products which do not fit within a specific monograph. Because an NDA is extremely expensive to obtain, due primarily to testing requirements, most Over-The-Counter Products substances produced in the USA are sunscreens, anti-microbial and anti-fungal products, external and internal analgesics such as lidocaine and aspirin, psoriasis and eczema topical treatments, anti-dandruff shampoos containing coal tar, and other topical products with a therapeutic effect.

The Federal Trade Commission regulates advertising of Over-The-Counter Products. This is in contrast to prescription drug advertising, which is regulated by the FDA.