Biologics, also known as biological medical products, are a class of pharmaceutical drugs that are manufactured in, extracted from, or semisynthesized from biological sources. They are different from conventional drugs in that they are composed of complex mixtures of substances, such as sugars, proteins, nucleic acids, or living cells or tissues, and are isolated from living sources such as human, animal, plant, fungal, or microbial. Biologics are used to treat a wide range of medical conditions, including arthritis, cancer, and autoimmune diseases. They are a subset of a class of medications called disease-modifying antirheumatic drugs (DMARDs) and are more complex and harder to make than conventional DMARDs. Biologics can be administered via injection or infusion and are regulated by the United States Food and Drug Administration (FDA). Biologics have had a profound impact on many medical fields, primarily rheumatology and oncology, but also cardiology, dermatology, gastroenterology, neurology, and others.