Which agency ensures that animal drugs are safe and effective before approval?

The agency responsible for ensuring that animal drugs are safe and effective before they are approved is the Food and Drug Administration (FDA). The FDA plays a critical role in the regulation of veterinary medicines and their approval process. This includes reviewing data from clinical trials that demonstrate the drug's safety, effectiveness, and proper labeling. The approval process helps to protect both animal health and public health by making sure that any medication used in animals meets strict safety standards.

The Centers for Disease Control and Prevention (CDC) primarily focuses on public health and disease prevention in humans, not specifically on the approval of animal drugs. The United States Department of Agriculture (USDA) regulates certain agricultural products and oversees animal health but does not handle the drug approval process. The Federal Trade Commission (FTC) is involved in consumer protection and competition but does not have a role in regulating animal drugs. Thus, the FDA is the correct answer as it directly oversees the evaluation and approval process for veterinary pharmaceuticals, ensuring they are safe and effective for use.