Shortcomings in the Pure Food and Drugs Act had been obvious since it became law. One weakness was the lack of authority to stop distribution of dangerous preparations claiming to reduce weight.

In 1934 the Office of Drug Control, headed since 1931 by physician Frederick J. Cullen, began investigations on products containing dinitrophenol. This was a component in diet preparations that increased  metabolic rate

to dangerous levels, and it was responsible for many deaths and injuries. Since the law did not mandate drug safety, the Office of Drug Control could not seize the products, and was limited to posting warnings.