Over-the-counter drugs, commonly known by the acronym OTC, are simply medicines that can be sold to the general public without a prescription from a health professional. They are the opposite of prescription drugs, which do require a valid prescription from a physician. In most countries, over-the-counter drugs are selected by specialized regulatory agencies to ensure that the ingredients within the drugs are safe, and that they can be taken without being prescribed by a physician.

These drugs are typically regulated based on their active pharmaceutical ingredients, not their final products. By regulating the active ingredients rather than the final products themselves, manufacturers are provided with more flexibility when it comes to developing an effective OTC drug. The term over-the-counter might appear a little unorthodox, or even ...