Therapeutic agents are substances used to treat, prevent, or diagnose diseases and medical conditions. They can include a wide range of products, such as medications, vaccines, and biologics. These agents work by interacting with specific biological pathways in the body to restore health or alleviate symptoms. Therapeutic agents can be classified into various categories, including antibiotics for infections, analgesics for pain relief, and antidepressants for mental health issues. Each type of agent has a unique mechanism of action, targeting different aspects of disease processes to improve patient outcomes.