Pharmaceutical drugs are substances used to diagnose, treat, or prevent diseases and medical conditions. They can be derived from natural sources or synthesized in laboratories. These drugs are carefully tested for safety and effectiveness before being approved for public use by regulatory agencies like the Food and Drug Administration (FDA). Pharmaceutical drugs come in various forms, including tablets, capsules, injections, and topical creams. They work by interacting with the body's biological systems to alleviate symptoms or cure illnesses. Common examples include antibiotics for infections, pain relievers for discomfort, and vaccines to prevent diseases.