In the case of Weinberger, Secretary of Health, Education, and Welfare v. Bentex Pharmaceuticals Inc., 1972, the Supreme Court ruled in favor of Weinberger. The issue at hand was whether or not Bentex Pharmaceuticals had to prove that their drug was effective as well as safe before it could be marketed to consumers. Prior to this case, pharmaceutical companies only needed to demonstrate a drug's safety for approval by the Food and Drug Administration (FDA). However, an amendment passed in 1962 required proof of both safety and effectiveness. Bentex argued that they were exempt from this requirement because their product had been on the market prior to 1962; however, they failed to provide substantial evidence supporting its efficacy during FDA hearings held between 1963-67 under "grandfather" provisions which would have allowed them exemption if proven effective priorly. The court decided against Bentex stating that even though a product may have been on the market before new regulations are put into place does not mean it is automatically exempt from those rules.

In the dissenting opinion for Weinberger v. Bentex Pharmaceuticals, Inc., Justice William O. Douglas argued that the Food and Drug Administration (FDA) had overstepped its authority by banning a drug without first holding formal hearings as required by law. He contended that due process rights were violated when the FDA issued an order to withdraw approval of a new drug application based on safety concerns without providing manufacturers with an opportunity to contest those findings in court. Furthermore, he disagreed with the majority's interpretation of "new drugs" under federal law, asserting that it was overly broad and could potentially encompass any changes made to existing drugs regardless of their significance or impact on public health.