According to the FDCA of 1938, what must be proven before drugs can be marketed?

Under the Federal Food, Drug, and Cosmetic Act (FDCA) of 1938, the primary requirement established for drugs before they can be marketed is their safety. This legislation was a direct response to public health concerns arising from unsafe drugs being available on the market, most notably highlighted by the Elixir Sulfanilamide tragedy where a toxic product resulted in numerous patient deaths.

As a result, the FDCA mandates that manufacturers provide evidence of safety for their drugs prior to approval for market entry. While effectiveness and quality are critical for a drug's overall utility and can be addressed through subsequent legislation and regulatory efforts, the foundational requirement established by the FDCA focuses specifically on ensuring that a drug is safe for consumption. Affordability is not a criterion that the FDCA encompasses, as it deals with the market availability and pricing of drugs through a different set of considerations.