Biomedical research is the pursuit of answers to medical questions. These investigations lead to discoveries, which in turn lead to the development of new preventions, therapies and cures for human and veterinary health. Biomedical research generally takes two forms: basic science and applied research. 

Basic biomedical research is the quest for knowledge about how organisms and pathogens function. The applicability of these studies to human health may not always be immediately obvious. For example, one might question the purpose of determining the precise molecular structure of the vitamin folic acid. However, it was this type of investigation that led directly to the synthesis of the first successful anti-leukemia drugs during the 1950s and 1960s. Used in combination, these medicines halved the death rate for leukemia, which had been the second greatest killer of children during the mid-20th century. 

Nearly every drug, vaccine and treatment is based on years of physiological research, medical knowledge and pharmacological insight. In the 1920s the Canadian research team Banting and Best discovered a way to control insulin in diabetics through research with dogs. This medical breakthrough was made possible by the accumulated knowledge of chemistry, cell biology, mammalian biology and applied medicine that had already taken place. For every headline-making medical treatment the public hears about, there are hundreds of studies that brought human knowledge to the point where it could be developed.

Living things are extraordinarily complex; we understand only a small fraction of the interactions, structures, chemicals, and pathways in the human body. So, the best way to determine the effect of a drug or disease on an entire living system is by studying it in an animal. Physicians and researchers overwhelmingly agree that animal models provide invaluable and irreplaceable insights into human systems because there are striking similarities between their physiological and genetic composition. Scientists are required by international law to conduct animal research before they test new medicines in people.
 
The biomedical research community is a strong proponent of the "Three R's": Reduce, Refine, Replace. Scientists themselves, as well as the oversight bodies that regulate animal research, may not conduct research on animals when there are appropriate alternatives available, or when the potential benefit of the research is unclear. However, animals will continue to play a vital role in research for decades to come. For example, the successful sequencing of the human genome has led to an explosion in exciting research involving genetically modified mice and rats. Scientists can breed animals that express diseases ranging from Alzheimer's to muscular dystrophy. Then, they can conduct research with the goal of curing those conditions.