The regulation of the use and distribution of drugs in the United States is governed by a complex set of state and federal laws and regulations. These laws and regulations are designed to accomplish a variety of purposes. First, the federal government hopes to exclude from interstate commerce drugs that are not both “safe and effective.” This function is performed by the United States Food and Drug Administration, exercising its authority under the Food Drug and Cosmetic Act and involves, for the most part, regulating the manufacturers of drugs. Second, both state and federal laws and regulations exist to keep “controlled substances” out of the hands of individuals who would use (or abuse) such substances for recreational as opposed to therapeutic purposes. The regulation of the use of such substances is primarily accomplished by the federal Controlled Substances Act (CSA) and similar laws that exist at the state level. Third, some drugs, because of their toxicity or habit-forming qualities, are prohibited from public consumption without the guidance of a health care professional. Unlike over-the-counter drugs which may be purchased by anyone, these drugs may only be purchased by a consumer who presents a valid prescription to a pharmacist.