Which agency is responsible for ensuring that medications do not cause harmful side effects?

The Food and Drug Administration (FDA) is the agency primarily responsible for ensuring that medications are safe and effective for public use. This involves rigorous testing and evaluation processes to assess the potential side effects of new drugs before they can be approved for marketing. The FDA reviews clinical trial data that evaluates various aspects of a drug's safety, efficacy, and possible adverse effects.

Furthermore, the FDA monitors post-marketing safety through the adverse event reporting system, enabling them to track and respond to harmful side effects that may emerge once a medication is in general use. This oversight is crucial for maintaining public trust in the healthcare system and protecting patient safety.

In contrast, other agencies mentioned have different roles; for instance, the Centers for Disease Control and Prevention (CDC) focuses on public health and safety, particularly disease control and prevention. The Environmental Protection Agency (EPA) is concerned with environmental protection and regulations, while the National Institutes of Health (NIH) is primarily involved in biomedical research rather than the regulation of pharmaceuticals.