More than 24,000 hospital patients were reportedly given the wrong treatment last year in England and Wales, leading to death and serious injury in some cases.
The National Patient Safety Agency (NPSA) has issued new guidelines on wristbands after more than 2,900 incidents were estimated to be related to their use.
NHS trusts across England and Wales use a variety of bands, with colours meaning different things. But the NPSA said these bands must now be standardised to cut down on errors.
