Electronic health record (EHR) systems are now in widespread use in healthcare institutions worldwide. EHRs include sensitive health information and if they are integrated among healthcare providers, data can be accessible from many different sources. This leads to increased concern regarding invasion of privacy and confidentiality. Incorporating consent mechanisms into EHRs has the potential to enhance confidentiality. However there are both positive and negative effects from employing such mechanisms--they need to balance privacy, safety, consumer and public interest.