 
 <prompt> Wetin be di minimum level wey drugs wey dem introduce suppose reach wey law talk say dem must dey effective? Based on di question wey dey before, write small tori wey get di answer. E fit be 1 - 20 sentences. Context: <response>: The thalidomide wahala bring back Kefauver bill wey dey enhance drug regulation wey bin dey stuck for Congress, and the Kefauver-Harris Amendment become law on 10 October 1962. Manufacturers from now on go need prove to FDA say their drugs dey effective and safe before dem fit enter US market. FDA get power to regulate advertising of prescription drugs and to set good manufacturing practices. The law talk say all drugs wey enter market between 1938 and 1962 must be effective. An FDA - National Academy of Sciences study show say nearly 40 percent of these products no dey effective. Another study for over-the-counter products start ten years later. 