Blockchain technology enables the creation of immutable, publicly available data. Initial applications have been primarily in the fields of finance (Bitcoin) and law (smart contracts), yet it can also help advance science by reducing human bias. The blockchain can ensure that hypotheses are not altered; that methods of data collection are transparent; that results are publicly available for independent analyses; and that conclusions are less biased. Our current system of medical research suffers from too much bias. Blockchain technologies, by creating immutable data, will lead to an increased confidence in evidence based medicine.