The increased longevity of humans over the past century can be significantly attributed to advances resulting from medical research. Among the major benefits have been vaccines for measles and polio, insulin treatment for diabetes, classes of antibiotics for treating a host of maladies, medication for high blood pressure, improved treatments for AIDS, statins and other treatments for atherosclerosis, new surgical techniques such as microsurgery, and increasingly successful treatments for cancer. New, beneficial tests and treatments are expected as a result of the human genome project. Many challenges remain, however, including the appearance of antibiotic resistance and the obesity epidemic.
Most of the research in the field is pursued by biomedical scientists in cooperation with molecular biologists.
New treatments come about as a result of other, earlier discoveries — often unconnected to each other, and in various fields. Sometimes the research is done for non-medical purposes, and only by accident contributes to the field of medicine (for example, the discovery of penicillin). Clinicians use these discoveries to create a treatment regimen, which is then tested in clinical trials.
A clinical trial is a comparison test of a medication or other medical treatment, versus a placebo, other medications and devices, or the standard medical treatment for a patient's condition. Clinical trials vary greatly in size: from a single researcher in one hospital or clinic to an international multicenter trial with several hundred participating researchers on several continents. The number of patients tested can range from as few as a dozen to several thousands.
In the United States, the most recent data from 2003 suggest that about 94 billion dollars were provided for biomedical research in the United States. The National Institutes of Health and pharmaceutical companies collectively contribute 26.4 billion dollars and 27.0 billion dollars, respectively, which constitute 28% and 29% of the total, respectively. Other significant contributors include biotechnology companies (17.9 billion dollars, 19% of total), medical device companies (9.2 billion dollars, 10% of total), other federal sources, and state and local governments. Foundations and charities, led by the Bill and Melinda Gates Foundation, contributed about 3% of the funding.
Fields of biomedical research include: